Honestly, you ask a decent question and judging by the number of posts you are fairly new to this forum. Thats no problem at all, and I welcome you here by the way. You should try doing a search here. This subject is a classic and usually starts a small tactical nuclear war. Many opinions abound. Run a search and if you still have any questions, ask away!
The honest answer is that there isn't a concensus. The best advice I have heard is to buy a FLGR if you have the short one and but the short one if you have the full-length and try them both and find out for yourself. The parts are cheap enough and this is the only way you are going to know for sure what is best for your gun.
I have archived numerous threads on this topic. Run a search in the gunsmith archive.
With that...we'll close it and avoid the normal routine.