If you never used in-ear, which I had not until I got these, you should realy try it out.
I will never go back to a monitor.
I use these mainly with an e-drum kit and find it works great.
One big reason for trying in-ear to start with, is that in one band I play all songs to a click track and have to use headphones. They just don´t look alright on stage and a lot don´t cancel noise well enough. You will not have any problems with that with these. Like regular industrial ear plugs these make you not hear what other people are saying but you also talk VERY LOAD :)
The sound is great, for being a small unit. Of course bass is not gonna be at par with a nice set of headphones but there´s definitly enough for a pleasant sound.
I can turn down the volume a lot because the noice cancellation is so good. So not as much ringing in my ears at the end of the gig, which to me is one of the biggest advantages with in-ear.
I was worried that I would have a hard time getting a proper fit, and at the first and second gig I was struggling a bit. But after a few tries they sit perfect and don´t move at all. There´s a lot of different "ear pieces" in both rubber, foam and plastic and many sizes.
So all in all this is one of favorite piece of kit.