As a general rule this article could be true. My experience with Zecco is mainly purchasing large cap liquid stocks, trading at more than $20, whose bid/ask spread is typically one-two cents. ( i don’t trade A/H). How does purchasing 50 shares at $20 at Zecco versus purchasing 50 shares at $19.98 + $1 commision at IB differ?

There’s one thing as an investor that you should realize and it is that spreads will vary but commissions are fixed.

I couldn’t understand some parts of this article, but it sounds interesting…

For example if you are more likely to get a fill at the ask of $25.00 and you submit a limit order in between the bid/ask at say $24.95 odds are you won’t get filled unless the ask comes down to $24.95.

One way or the other you will feel the effects when you have a non-direct access broker.