For Mutual Fund, it actually depends on the fund companies whether the fund is a no-load mutual fund or front-load mutual fund or end-load mutual fund. Most mutual fund no-load mutual funds then they're free of service charge. However, you have to hold the mutual fund for 3 months after purchase. Otherwise you will be charged 2% - 5% service charge depends on the fund.
Your second question, there's no annual service fee. They charged you by per-trade commission for equity trades. I found their commission is quite average comparing to TD Waterhouse or other big online trading companies.
How I feel? so far so good. I hardly try buy/sell at real time so I can't tell how fast they can fill your order. (I always use limit buy/sell). But I remember they have the policy to fill it within 1min (or 5min). I forget the policy but you can find out from their web site.