I personally started on authentic's since there wasn't a huge market for clones back then. I own both now and some clones do make improvements over the original's, some are crappy and not worth the cheap price tag and others are on par with the original's. It all depends on which one you are looking at. I have ordered from places like fasttech and certain things do come out better. Mod's I never had any issue with, rba's were a whole other story(this was last year, so it may have gotten better).
Keep in mind that if this is your first one, you may want to find relatively inexpensive items as it may not be for you. My buddy went out and purchased a really nice authentic mod and topper. Only to find out he didn't care for it, now it just sit's there and he uses his mvp daily.