Either way will be fine if done by a competent professional. I'm old-school and like iron sleeves. But I'm in a tiny minority. Most prefer replating. As you've probably researched, you get better heat transfer and more even expansion of piston/cylinder with replating. Done right, they can last years in mild trail riding with proper maintenance. Downside is you can't easily overbore and grenading a piston or a ring usually means another replating. With sleeve, you bore up .5mm, hone and throw in a new slug and rings. But it is easier to have a cold seizure with sleeve as sleeve expands less rapidly than piston during warm-up; heat transfer isn't as efficient; and ports on sleeve are often less than optminally matched up to cylinder. Done properly, either is fine. The key is really about the craftsmanship of the work being done. Finding the cheapest route isn't always the best. Having said that, I'm a Wiseco piston guy and I'd drop the extra cash for one, either way. No experience with namara, good or bad.