I first bought one of these kits about half a year and it was my first attempt to build a guitar. If you want a cheap guitar; you can't really get better for the money than this kit, but it does require some work to get it finished super nicely and a lot of time and swearing at getting it set up if you're doing it for the first time like me.
The manual states that it's basically ready for lacquer, but I'd recommend a few steps before you do that. The first is to ALWAYS use a coat of primer on the wood, not only will it help the paint stick to the body, but it's a perfect way of finding the rough spots in the wood before you put your expensive paint on.
This way, I could see that on my first kit, the body required a bit of sanding around some of the edges and there were a few 'dimples' in the basswood that I filled up. Once it is all prepped and you spray the paint on, it'll look magnificent but if you skip these steps, your guitar might not look all fancy and new and you might have to repaint it several times.
There are plenty of options to really make this guitar your own. It comes with a paddle headstock that you can make any shape that you desire, and even do inlay work if you want. The chrome plate for the bolt-on neck can be easily engraved with something personal and because you've built it yourself and (hopefully) now know how the guitar works, you can easily change parts.
Be careful though, if you buy a Fender/Squier all the parts and sizes will be standardized. This is not the case with Harley Benton. I purchased a pearloid HB pickguard for this HB kit and it didn't fit at all. All the screw-holes were off and it was simply too tall to even fit between the neck and the bridge, meaning it's useless for any standard 22 Fret Stratocaster with a 25.5" scale length. Other than that though, mostly everything else is interchangeable.
I recently started building one for a friend as well. Upon opening the box I saw that some slight changes had been made in the body lay-out. The entire cavity where the wiring is was now deeper, rather than just the bit where the 5-way switch is located, and the ground wire now went into the rear cavity from the side, rather than straight through.
When spraying primer I found that the body wasn't sealed at all and it was full of tiny holes and pores. I emailed Thomann and they sent me a replacement, which was the older style I also got with my first kit and that one was fine. Service you won't get when buying a Chinese kit from eBay, but it is a little point to pay attention to when you receive your kit.
One thing I did find funny is that they replied in an email that the body won't be ready for paint when you receive it even though the manual says the following direct quote: "The basswood body of the guitar is sealed and prepared for various types of lacquer coating. A wide variety of
finishes can be procured from DIY, timber and automotive outlets in aerosol cans making finishing straightforward
without requiring specialist skills. The use of a dust mask is essential when spraying."
The features on this guitar are just standard Stratocaster stuff with no real extras, which you honestly couldn't expect for the price either. It comes with 3 ceramic single coil pickups, a floating tremolo bridge, a 5-way switch to select one or 2 pickups at a time, a volume knob and two tone knobs.
For ?70 didn't expect much, I just wanted an electric guitar that I could play while saving up for a nice Epiphone Les Paul. I got more than expected though. The parts are cheap, there's no denying it. But the tuners are surprisingly good. I left the guitar for a week when I went abroad and when I came back it was still... actually perfectly in tune? I was confused by that to be completely honest, I did not expect that.
Other than that the bridge just works as you'd expect. The nut is plastic but I suppose it can be changed if you want. The inlays are plastic but it doesn't really matter and they look nice. The frets are mostly level and nicely sanded down to protect your fingers and the electronics just.. work.
The strings do feel excessively cheap and they're not colour coded which resulted in me having an incredibly difficult time telling the B and G strings apart on such a light gauge. The .009 strings do play easy though and cause I went for a classic strat I kept that size, but bought a pack of Fender 150L strings which will cost you around ?4 from Thomann, and it's worth it.
As said a lot can be customized to your liking on this kit, and because you built it yourself, you'll always know how to take it apart and change components at a later stage. You can do whatever you like with the body; Spraypaint, custom marker designs, a nice painting, wood stains, etc. It won't look great with stains though as the wood not only looks a bit bland, the bodies are usually made up out of several pieces of basswood that don't always match colour and it's definitely not a centerline either.
On the one I made for my friend, I had a custom pickguard made out of semi-transparent frosted red acrylic which looks awesome, so when you throw a bit of money towards these guitars (and a lot of time) you can make them look very original and pretty.
The guitar sounds alright. It's a very light sound with the basswood body, single coil pickups that have ceramic magnets on them, and .009 gauge strings. The pickups and strings can be changed, but changing the pickups will require soldering and probably cost you as much as the entire kit costs (although to be honest ~?150 is a VERY good price for the guitar that you'll have then).
There's nothing you can do to change the basswood body though and I wish Thomann would start selling kits with Alder bodies, or Mahogany for the Les Paul style kits. Or maybe just separate necks and bodies since all other European webshops already seem to ask ?50 for a maple neck OR a basswood body, while at Thomann you have both + all the electronics for ?70. I'd also love to see a maple fretboard option cause I went for a '50s looking strat which means I now have to purchase an additional neck from some place else.
All in all this is a very decent kit for the money at stock. Just pour some time and love into them and for around ?100 (kit, paint, strings, etc) you'll have a gorgeous classic stratocaster style guitar that you can't buy anywhere else and maybe even has your initials engraved in the chrome neckplate, or your name on the headstock.
Or just be completely unbranded and it won't look as cheap as cheap guitars do. Unfortunately it does sound pretty 'cheap', but so will any strat that you buy for even <?200 and you wouldn't have the fun of making it your own, nor the knowledge of how to make it better later down the road.
If you were to change parts, I'd recommend to start with the pickups. They really are very light sounding and if you're looking to get a heavy sound out of this guitar, you're going to need a good distortion pedal or something like a Line6 Spider amp. Obviously if you really want nothing but a heavy sound, you're better off looking at the Les Paul style kits that at least have humbuckers in them but these are nice all-rounders and ST guitars are the perfect beginner guitars due to their variety in sound with 3 different pickups.
You have to be careful with replacement parts as even Harley Benton pickguards don't seem to always fit these kits and Fenders definitely won't (trademark issues and all that). I bought a Fender replacement kit (knobs, tremolo arm cover, switch cover, pickup covers and backplate) and things like the switch and knob covers will fit, but the tremolo arm was too wide to fit the replacement on and the pole pieces on the pickups weren't spaced properly, so that one cover did not fit. The backplate did fit, although the screwholes were different, but that's not an issue.
All in all this is a really good kit, and I would buy it again if someone asked me for a cheap guitar. This is the best < ?150 stratocaster that you can buy if you give it a nice paintjob and a good set-up. You can easily upgrade/replace all parts like the bridge, tuners and pickups, but not all cosmetic 'upgrades' will fit.