The answer to this question will have to do with the ankle strength of the person buying the skate.
There are 2 factors you have to look at, boot cuff height and wheel size.
Speed skate wheels come in 80mm to 125mm wheel height.
A person has to see at what height off the ground they cannot properly stabilize their skates (skates become wobbly).
If you try an 80mm wheel and you are stable then move up to a 90mm wheel.
You continue to go higher in wheel height till you feel instable, then back down to the last height that felt stable.
The 2nd factor is boot cuff height.
The higher the boot cuff the greater the stability, the lower the boot cuff the less stable the skate will feel.
Say you have a low cut boot and are stable on 100mm wheels. Now you want to move to 110mm wheels but the skate becomes unstable with 110mm wheels. Moving to a higher cut boot may allow you to skate on 110mm wheels due to the greater stability of the higher cut boot.
So the answer to the question "What is the best inline speed skate?" is, what ever height of the boot and wheel that you feel stable on.