I use TM2008 preview4, Tencent's new IM for English speakers designed for businesses. It's fantastic. I like it better than all the other IMs I've tried except Google Talk, which is more of a no frills chat program. Apples and oranges really.

Tencent has greatly improved their English versions with this product. The earlier versions of QQ in English, frankly, stink. This one is awesome, even in this beta version.

Management at Tencent appears to be taking internationalization and localization very seriously, and their new professionalism shows in this product. I have had some contact with their International Product Center since trying it, and the people are driven to produce the best IM they can and are always helpful. I highly recommend it.