Welcome.

There is no such thing as best custom rom la

All comes down to self preference..depending on what you want...then is easier to choose. So you want slim, themeing, close to stock rom etc?

If you are new enjoy your stock rom which is way good enough for most users
Only freaky users like some of us wants to test custom roms just for fun
This is one phone I m most happy using the stock rom
Telling you from a very experienced rom flasher