I haven't finished either, but the only reason to replay previous levels in either is to improve your time, which for me isn't very compelling. I'd say neither has much replay value, at least no more than your average puzzle (not falling block) game.
The best you can do is put it aside for a few months and then try again once you've forgotten the solutions. It's not like Super Mario Brothers where you can finish the whole game and then play it again immediately, still enjoying it. Not to me, anyway.