This was partly made for wondering what the community's favorite leaderboards/achievements app is (if someone can word this better just tell me), and partly for developers to decide which one would be a better choice to put into their apps
Defenitely OpenFeint. It probably has the most unique design ever for a leaderboard/Achievements. I really don't know why, but I seem to hate Plus+
Plus. It's sleek and fast. OpenFeint is dragged down with the never-ending pages you have to go through to change your profile, see friend requests, etc. Plus interface is extremely simplistic and easier to use.
Crystal. I really like how it is stylized to fit the game it is implemented in. It is happy medium between plus+ and feint. It is a good bit faster than feint (although lacks many of its features) and has more features than plus+ (while not being as fast)
I like OpenFeint, simply because of how many games have it and how easy it is to activate it for each new game. No need to type in a username and password. You can also view achievements while offline. I don't like Plus+ because of the fact that you can't check achievements without being connected to WiFi/a phone network. I play my iPod on the train to and from school, and not being able to see the achivements is a pain. Agon is very nice, but not many games use it. I've only got one game with Crystal (Angry Birds), and it's been very bad with recognising achivements I've gotten while offline.
Faster...? For some reason, at least on Angry Birds, it takes like 2 minutes to load a leaderboard section... My favourite is Plus+ though.
Openfeint has the most apps and im just used to it. I don't know why but i hate plus, it just really annoys me i have never used agon and i have used crystal once and think its kinda confusing.
OF. Somehow I dont like ++ that much (must be because of that horrible, non sensical name). Crystal and Agon are nice, but they really can't measure up to the 2 that have been up for a lot longer.
I'm actually warming up to Crystal quite a bit. I like its interface, its slickness, and everything about it so far. So far, it also loads a lot faster than Open Feint, at least for me. I think I may actually have to choose Crystal. Open Feint is nice, Plus+ is cooler, but Crystal... I don't know. I really like it
Ya I've heard it being really laggy for some, but for me it is much faster than feint and slightly slower than plus+
Plus+ is sleek? If by sleek you mean it has an achievements & leaderboards feature, and that's it, then sure. Fast? I didn't realize waiting for the achievements page to load for 2 mins is fast. I guess OF taking less than 15 secs is sluggish