My "top" rating I give here is 4 heads. If I rated your MOC that, it's my fantastic MOC rating and of high "flawless a/o admirable" praise. I do, very rarely, give a 5 heads rating, but it's reserved for those who have put forth an unbelievably exceptional effort of time or expense - i.e. hundreds or thousands of dollars and hours.
Star Wars MOC's are typically my favorites, but I do love just about anything well done, especially in the Space, Steampunk, or Apocalego genre's.