i love IEMs but i've never "needed" a blaring amp behind me. if it was blaring, it's only because the room or band was too loud to hear myself.
i play in several crowded restaurants regularly, and the crowd noise from talking and clanking utensils is way louder than what they allow a stage monitor to be. in fact at one place, they want zero stage sound, only sound through their mains around the venue.
IEMs work perfectly for this, as i can hear myself clearly, no crowd noise except what bleeds into the vocal mics. i actually sing way better and more comfortably (high notes, etc.) with IEMs. guitar sounds great. i can't have an amp here anyway. these gigs are BRUTAL without IEMs. it's a no win.
the weirdest thing is that there is no guitar sound, but just someone singing to nothing if you're extremely close to the stage. because - you guessed it - they don't turn the mains up much at all. mostly out of fear for "blowing up" the speakers...
but you'd be surprised - as quiet as the mains are, people from all over the restaurant pass me to say "you sound great thanks!" as they leave the venue. so it's not about being loud. people can hear it. and they appreciate that it ISN'T loud.
of course this is one specific gig type. but it IEMs are the perfect solution. i also enjoy IEMs at bigger gigs when possible.
it's well worth the time needed to get used to them. and if you have a capable rig, you can mix your own monitors - or show up with it premixed. and that saves a ton of setup time, and of course reduces headache during the gig.
for bigger bands that feel sterile on IEMs, consider adding a room mic in the center of the stage for some ambience, just dial it in to taste. the lack of room sound i find is what makes people hate IEMs. or try any reverb available on your mixer. i always need a bit of that or it feels dead.
