I've been trading in Profiforex several months, they provide fixed spread, and spread is from 2 pips. Profiforex MetaTrader is great. I am very impressed by execution. Demo is exactly the same as real.
All brokers who have fixed spreads - really don't have it. You can check your agreement with broker and you can find - normal and not normal conditions for market, it means that on important market news it can be higher then 2 pips.
I can recommend you to try nordfx - they have 2 pips on micro account, and also they give 8$ for free on welcome account, so you can try their real conditions for free. And aslo they have mt4 and mt5.
I use them and it is fine for me.