So this review might be a bit dated (I lived in Cleveland from March 2006-December 2008) but I used to go to Mercury Lounge quite a bit. I never really "fit in" in Cleveland, I was born in NYC and grew up in DC so I'm a somewhat typical East Coast guy. The midwest thing never really felt right for me, that being said, there were a handful of places in Cleveland that suited my fancy while I was stuck there and Mercury Lounge is one of them.
I worked a ton of hours when I lived in Cleveland, 70+ every week so I looked for places that could satisfy my urges without me having to bounce around too much.
I liked Mercury because they had good DJs. I'm not really into House or even DJs in general but I tended to like the music I heard there and more importantly, so did everyone else, which led to a good vibe. I like the patio out front a lot, I would usually post up out there 8 months out of the year with a few friends and make it happen. It was great, the servers were all just fine (for an establishment of this type-they're never going to amaze you) and the drinks were always poured pretty strong.
I don't remember the Bar Manager's name but he was great and I bet he is still there. He was featured in a few magazines and was pretty well known around Cleveland for making good drinks.
Hope it still stands up!