The place has an upstairs bar with a terrace and a downstairs club. Live gigs fairly often. Because of the central location it draws a very mixed crowd.

The upstairs bar isn't a bad place unless it's the weekends when it can get too packed. Wouldn't recommend paying for the downstairs club unless there's a live gig which you want to see. Or you're drunk and with good friends (in which case pretty much any place can be fun). When there's no band the music varies a lot. I guess because they get so many laypeople there the DJs play a lot of non-rock/metal stuff.

On the Rocks is a cool bar to go to with friends for a bit of glam/classic rock. It is very central, so gets packed, but not with a metal crowd. For metal, not rock, head to PRKL just around the corner.

We were in On the Rocks on Halloween 2007. First to say: We only on the "Bar-Level". The atmosphere was very nice and relaxed, the service was quick and the decoration regarding Halloween was not such an overkill as usual. The prices were the same as in all other locations in Helsinki we visited, at least regarding the beer-on-tap (if I remember correctly there were four differen beers on tap plus two Cidres on tap). The prices for the bottled beers (which were more then ten different ones) may differ.
Altogether: It's nothing special but very nice.

Don't go there, unless there's a band you definately want to see. The beer is expensive and there are hardly any places to sit. Too central to be nice.

I've been there twice to see bands (Tarot, Charon) which play in the underground (cellar) level.
Great small venue--wide and slightly multi-level to allow good views of the medium high stage from almost everywhere.
Sound quality is good. Stage lighting is good for photography providing the smoke machine isn't on overdrive.
The DJ played plenty of well-known Finnish melodic metal band between sets.

Im a big fan of rock clubs and live bands so I was excited to see this listing. Sadly the reality was not so great. Very few seats unless you wanna be on the bar terrace, quite unfriendly atmosphere to be honest. I wouldnt go back.