I generally don't feel uncomfortable interviewing in a suit regardless of what they are wearing. My current job, the agent explicitly told me to wear a conservative tie, suit, polishing shoes etc and the hiring manager was in jeans. In some ways it actually makes me a little more relaxed because (rightly or wrongly) it gives me the impression they aren't going to be judging me on my appearance so I'm not say there thinking 'is my tie knot done properly?' or whatever