MOTU M4

I'm using this in my home studio setup, connecting two pairs of monitors, headphones and some mics and guitar.
The build quality is great, metal chasis and pots, beautiful LCD display with meters, and rubber bottom pads so it doesn't slip around.

The headphone amp drives my 250 ohm DT990 without a problem. I keep it at about 60-65% while mixing and at about 50% for mastered material and it is loud enough for me, with a lot more gain if you need it.
Sound is crystal clear, which is expected as it has professional converters.
The only thing that bugs me is that there is no volume control for output 3/4, at least no practical and fast way to do it. So switching to my secondary monitors to check the sound is a bit of a hassle.

Pros:
Sturdy build, clean converters, great LCD, two pairs of outputs, good headphone amp.

Cons:
No volume control for output 3/4

The m4 is definitely worth its price.
Build quality is really good, Encoders feel smooth, buttons clicky and responsive.
The connections aren't wiggly and usb c is perfect.
The outputs are solid too especially have 1/4" jacks for both 1&2 and 3&4 outputs.
Inputs are crisp and low latency, good enough for me to play guitar.
The screens are helpful and the headphone jack drives my headphones very well.
The asio is simple to use as well as the loopback feature.
To use this for music production/podcasts is a no brainer this fits the bill across the board.
My only issue is that loopback, line in (3&4) monitoring, volume knob and headphones all only work through 1&2 output channels. If you use your computer for a multitude of tasks, I imagine gaming or DJing would be under it- I like to route my game audio through my speakers and have voice chat through my headphones and would furthermore like to use my headphone output for cueing when Djing. However you can't have the headphones use 3&4 output channels. I have instead been using 3&4 outputs as my main audio from my computer. This basically means I can't use the volume knob which becomes another unneeded issue to make sure all my software is turned down as, again, I can't control the incoming volume on the m4. It would be good is motu allows users to pick which outputs channels are for monitoring and headphones.
All in all this device is still one of the audio interfaces out there at the moment in its price range and would recommend to anyone.

Search on youtube and internet something like "windows drivers problem MOTU". Sound popping, crackling, distorting on playback no matter of buffer size, settings, USB Windows settings in device manager (power options, disabling drivers and kepp ASIO only etc)...

Tried on multiple computers. And this is well known problem. Be aware if you planning to use it on Windows, MOTU drivers are junk.... And you can tell that it is computer or Windows problems - connected another USB to the same computer, same port, same settings - no any issues. No any issues whatever with integrated sound card. With MOTU it's like back to stone age...

Very disappointed, bought because of overhelmed positive reviews (assume most on Mac users). And even if some people do not have problems on their PC on Windows, it is not appropriated that device is working 50/50, like you are gambling...

I´m very impressed. Look no further for a professional sounding audio interface for home studio and/or travel/gig rig. Easy to use and set up at a great price point. I´ve used Apogee and Apple computers for over 15 years. I´ve recently changed my personal home studio over to a Windows system (I'm glad I made that change) and after spending so long with Apogee was underwhelmed by "professional" audio interface options. I'm used to crystal clear sound and next to no latency! I thought RME was the only possible contender to use with Windows. Maybe the Neve 88M? (I no longer wish to use Apogee) However, as we all know, costs rack up quickly with gear purchases. I wanted to see if i could find a solid audio interface for a sensible price. I researched the current market and stumbled upon the humble Motu M2/M4. It´s indeed solid, nicely designed, and sounds/performs every bit as good as an Apogee/RME and for a fraction of the price. (The Motu M series even utilises ESS-sabre 32-ultra converters same as Apogee!) As yet (touch wood) not a single glitch. I have my Windows system optimised for audio and predominantly record live guitar, bass, vocals and use stereo, mid/side mic technique when recording acoustic guitars. We live in a great time for home recording and pro audio. Products costing €€€ no longer need to be the pinnacle of quality. Save yourself some money and buy the Motu M4. (It even has an on off switch!) You wont be disappointed.