I love IB! I only have Schwab to compare it to, but I love it! I hated having to figure out how much I could afford to buy in one order and how much I would have to make to cover commissions. Now I can buy in 100 share increments and build up positions. I know if I buy 10 100 share lots, it costs me $10 instead of $7.50, had I got them in one 1000 order... but it's worth the 2.50, since I was used to 19.95 or 29.95 per order. This way I have 1000 shares, usually at a lower price than my initial buy. Sometimes it may be higher, but I don't mind adding to a riser.
The only problem I had/have with IB is transfering equities. When I first opened the account, I put in an order to transfer a few holdings, and they only took part of it... apparently some of each were in cash and the other were margin, I guess the ones I held from higher than 5.00 were margin and the ones under weren't. They only transferred the margin ones. Maybe it was because I have a margin acct with IB, I don't know. But when I issued another transfer request, they just rejected it saying "account mismatch". The only other reason I can see is that my Schwab account is joint with my wife, and my IB is just in my name (figured I'd get it opened quicker). So transfering between account doesn't seem to work for me... but I can wire out of IB for free.. just costs me 25 to wire into it. Sending a check takes forever! 10 sessions after they acknowledge receiving it!
But other than the minor issues, IB is great! I just wish I could use HTML when I'm not at my home computer. The Java doesn't seem to work well through my proxy at the office.