I usually play 4 tables of zoom. I admit, though, that I can get a little overwhelmed when I'm actually in a hand on all 4 tables.
I don't understand how anyone can make money playing multiple tables. When I play a Sng, I need to know which players play tight, which ones are the maniacs etc. I found if I play just one table and focus on table dynamics I can almost always make it to the money. When I play in several at a time I almost always come out a loser.