If you like to backtest ideas and have a lot of automation with your trades (patterns, alerts, algorithms), then Arcade Trader is the new kid on the block. Otherwise, I use Robinhood for swing trading, just to buy and sell stock previously studied.
I have used IB, Lightspeed, Sierra Charts and TOS. Lightspeed does have instant execution but charting and platform capabilities can't come close to TOS. Their failure to match zero commissions make them unusable for a daytrader. Sierra Charts has the best overall platform but they do not support their program with stock brokers although I am told IB will allow them as a 3rd party app and one person on the Sierra Charts forum says it does work for him/her. I use TOS for stock daytrading because of the platform flexibility; for example you can have up to 32 stock charts on one screen simultaneously and also 32 individualized stock trading boxes pre set with the number of shares you want to trade for each stock on one screen. Their quotes are slow and trade execution is slow but I can live with that. If I have to wait one second for a fill I figure it even out over the long term.
The only units I can think of is "CASH". That is how I measure "pretty solid", and also "oh-so-marvelous". They are ALL measured in CASH, AKA, in MONEY earned, in pure profits. However, I cannot offer an opinion on how technology has advanced in the last ten+ years. So, I offer "CASH in pure profits", as a potential unit, and as a way of how to measure how these platforms compare to each other...
I have only used IB and Tradestation so far. IB execution speed is far better than Tradestation for sure. But IB commissions/fees are too high. I traded 6600 AMD and paid around ~$75 for that trade (including buy and sell). How much Lightspeed charges? I only care about execution speed and fees. Which one would you recommend. I heard Fidelity and Charles Schwab are better too.
I use CMC mainly, but looking for another alternative currently. I would like access to as many international markets as possible. I saw IB looked ok, but read on here they are expensive....