Shiren 6 was so fun. Felt better balanced than 5, in that once you obtained the "keys to a run," the game plays out much more consistently. And it felt like you found the "keys" themselves more consistently, too. One of things that annoys me in this genre is the feeling of helplessness when you're 1/3 through a dungeon haven't come across anything that can improve your chances of success. Even 6 has a couple dungeons like that, like the DLC one based off the ultimate dungeon in the 1st Shiren game, which makes most of the awesome runes and new features unavailable.
Anyway, I've been itching to get back to it. Got about 230 hours in it. I could stand to play some more 5 again, too, when it's not destroying my ass.