FYI, we support Mutual Funds trading for quite some time http://www.interactivebrokers.com/en/trading/pdfhighlights/PDF-ETFsMutualFunds.php?ib_entity=llc Also, see second to last tab here http://www.interactivebrokers.com/en/p.php?f=products
My advise is colored by my experience with them. They're just OK. Some things they excel in, such as product offerings; with other things, such as service, they are abyssmal. For me to say they are the "worst" would be as clear as smoked glass. Priorities of good service, executions, data, etc. to one trader are not to another trader. Indeed, I have had better, but if I were a new trader who wanted exposure and demo abilities with a vast array of products and a complex platform to learn on, IB would be in my list of top 5 brokerages. Also, if you are using third-party charts needing market data, and aggregate data is sufficient for your trading, IB provides market data for free if you trade more than $30 per month. This is not tick-quality data (esignal, etc.) but should do for stocks and options. For this end, it sure beats paying extra $ per month to a market data provider. - FORMER IB client of 10 years