Been using MBT for about 1 year now, no major issues to report. Spreads are not bad, usually get 2 or 2.5 on EURJPY, and have seen smaller spread (0) day to day. Commissions don't bother me and if you trade a high volume, you can speak to an account rep to lower the commissions.
Have take out lots of $$ from my trading account, wire transfers happen same day (pay $20 for the wire, no big deal for me).
Execution is fast, never had a requote.
Some people don't like the trading platform. I like that its just a trading platform. They now have MT4 which I use for my charting (set up a demo acct through mt4 software). also have some research and notes stuff if you're into that (i dont - never trust an analyst :))
Cust service could be better. Only had one issue - with my pw, and it took 2 days to get sorted out. A couple of times they had system-wide issues and couldn't log on for a couple of hours, but that hasn't happened in over 6 months.
Overall i'm pleased with the service.