I have used/ am using the following brokers for MetaTrader over the years - AvaFX, GoMarkets, AlpariUK, FXOpen, IBFX, FXCM, Lite Forex, Oanda and a few others.
To be honest I haven't found a huge gulf in difference between any of them. Even the best will requote you just when you don't want it, but this is more to do with the markets I think than the broker themselves.
In my opinion there are three things to consider when choosing your broker -
1) Pick a broker that is right for you and matches the strategy you want to trade. For example FXOopen allow accounts from 1 dollar which may be more suited to new traders who are starting out. For me they offer a great 'real money' way in which to test out systems rather than using a demo account. This leads me on to my second consideration...
2) Demo accounts are not a good way to test out a broker. You will get better spreads and execution on these as the deals are not actually being made in the market. In addition you will get attention from the broker up until the point that you open an account with them...
3) Remember that many of the smaller brokers are simply 'white labelled' platforms.
Also don' believe all the negatives you read about brokers. They are there to take your money, its there business, but many traders simply blame their brokers as an way to try to excuse their poor trading.