I've dabbled, let me emphasise a very small dabble mostly I observe, with $500 buy in on PokerRoom. The quality of player is variable.

I've seen 8 sharks, all two tabling the only 5/10NL tables being played, eating anyone who sat in the other two seats. While I was watching the most consistent winner stuck his nose in for one rotation and then dissappeared, no doubt to another site.

Conversely, on Friday or Saturday night, when there are usually around 10 tables going at 500 max buy in, I've seen people playing like idiots. You can always tell where the biggest whales are sitting by length of the wait list for those tables.