I installed 0.5.26 and so far I've only tested MSN but everything is working great. Even though it's still a beta, it's much more stable than other programs that I've used.
As for making it better I would suggest:
1. From the contact list, typing the first letter of the contact you are looking for so that you don't have to manually scroll through long contact lists.
2. Have the option for a separate group at the top for "current" conversations. Entries from this group would be removed once you manually end the chat.
3. Basic Emoticons
4. Being able to send/receive the MSN "nudge" requests
Great product, keep up the great work.