Let's look at the Speed Pro and compare it to the Ross Cardiac for the sake of argument. If you were to get perfectly spined arrows for both (which would most likely be different arrows because the Speed Pro would require a bit of a stiffer shaft), the Speed Pro would shoot an arrow 25 FPS faster without a decrease in brace height, without an increase in draw weight, and without a decrease in arrow weight. In fact the Speed Pro arrows may be slightly heavier. So, all things being equal there is nothing that would decrease the forgiveness of the bow. Now that speed has to come from somewhere, so the draw force curve would be much more aggressive. If you can handle the stiffer draw, even in cold weather, the Speed Pro offers a speed advantage.
Oh, but there IS something that increases or decreases the forgiveness and accuracy of a bow...
any bow... and it goes back to what Urban Redneck said about the human factor.
The grip.
The grip is the only part of the bow that the shooter is in direct contact with while shooting - assuming he's a release shooter. If the grip isn't comfortable and allow for consistent hand placement, then the bow is not going to be accurate, consistent or forgiving for that shooter. What does it matter if Bow 'A' shoots 30 fps faster than Bow 'B' if Bow 'A' has a grip that won't let you put two arrows into the same zip code?
If you're lucky and the faster bow has a grip your hand likes, or has an available aftermarket grip you like, then you're in business. If not, you're far better off with the bow that has a grip that fits, even though it shoots slower.
Fit and comfort should be the first two points on your list of priorities when choosing a bow. Speed? It should never be higher than #3... unless you plan only to use it to win Fastest Bow competitions.