Yes Les hearing yourself and hearing others can be a problem. It's hard to say without being in a situation. I play melody and mostly use a tenor banjo but sometimes take a mandolin instead. In the session I most usualy frequent, we can have Irish pipes, melodeon and piano accordian (one of each) going but I still can hear my mandolin (which admittedly is quite a loud one) with no problems.

I think the worst I had it in recent times was in some bash I went to where there was a lot of chatter and an incredibly loud accordion player. There were 2 of us playing banjo a couple of feet apart. I could neither hear myself or hear the other banjo to get an idea that what I thought I was playing was in sync with what the other banjo was playing.