If you want to use different keycap sets, don't buy a Razer keyboard.
If you are statisfied with the stock Razer keycaps, don't buy a Razer keyboard.
EDIT:
The Razer keyboards have a non-standard bottom row and 5 macro keys.
Aftermarket keycap sets usuallly don't have the keys for the non-standard bottom row. Aftermarket keycap sets also do not include caps for the macro keys. So if you want a different set of keycaps, you will have a hard time finding a set, that will fit exactly on your Razer keyboard.
If you do not plan on buying other keycap sets, or you don't mind it, that other keycap sets won't fit 100%, you can buy the Razer keyboard.