Sure, if platform is only front end and all the order handling logic on back end servers run by the broker. I assume “performance” means execution speed, not GUI stuff.
of course it can. All depends on the broker. Forex dealers used to have in their agreements that they reserve the right to quote different price to different people at the same time.
Not in US. most had to leave due to regulations that stopped shady practices. Outside US I am sure it is on. Most of them are bucket shops.
I'm mostly talking about connectivity issues and quote/chart lag. Also, what are desired technical parameters of brokers' backend?
The only platform I've used at different firms is sterling, and it is consistently very fast. I haven't noticed any difference. Kind of off topic, but I've tried proprietary platforms at a couple of firms, and they didn't come close. I switched to sterling within a couple of months in both cases. Thankfully, they both offered it.
The forex market has historically been a disaggregated market, for the most part, but it has been evolving to a more somewhat more traditional, centralized one. So brokers don't have to be considered automatically shady if they have different data among themselves. It all depends on which sources are supplied to each particular broker feed. But word gets around on those to avoid so D.Y.D.D.
Yes, I have had Sterling through NOMURA and have had a lot of delayed and lags and in this same day I have spoken with my friend, who also using Sterling and by him was everything ok.