I've been having a lot of fun with DS3 Seamless Co-op since it released recently.
It's so much fun to play these games with multiple people. And it was surprisingly stable. We've had a couple of crashes, but not worse at all. The only boss that was too bugged to play was Wolnir. Luckily it bugged out so hard it beat itself.
Can't wait to play DS with 2 players as well