Some crafting professions give roughly the same stat boost. Let's say I'm a warrior and my primary stat is Str. So what do we have:
Alchemy - potion that gives 80 str.
JC - 3 epic gems, that are superior to similar blue gems by 81 Str.
BS - 2 additional gem slots that provide you with, for example, 2 Str gems.
Inscription - 2 ring enchants providing you with 80 str.
Of course, by having these benefits, you don't have to sacrifice anything, I mean these enchantments do not overwrite other things.
Now here comes a special case - leatherworking. It provides you with 130 str enchant on bracers. However, you are sacrificing any other enchant your bracers could have.
But is that enchant really worth keeping, as pure stat bonus is usually much better.