This is constantly repeated like its gospel, and proof is never given
Let's see hard proof your order is not filled at the best bid/offer in a timely manner
If there's no proof forthcoming, then I will assume the folks pimping this nonsense are full of crap, 2000 posts or not.
Ha ha. In this day and age questioning in what way one might get screwed over is probably not so wise when there are a dozen proven ways. For example, you could sit the whole day on the bid and not get filled, even if you constantly adjust the price. If you send a marketable limit order, most often than not you might get what you wish for without any price improvement etc.
A better question to ask would be would there be any proof that ib pro delivers a beter execution service than lite? There are only a finite ways that this could indeed be so.
The proof is in the pudding.