I'm using Swype on my Eris and while I liked the leaked version, even though it would FC fairly frequently, I really like the beta. It is a lot more polished, fluid and more reliable. The couple of hours I went without Swype and had to use the HTC keyboard made me realize how reliant I had become on Swype!
FYI, I installed SlideIt but my phone would never recognize it, even though I had selected it like I did Swype. Needless to say, I'm sticking with Swype!