That's odd; LR 1.2 is very stable on my system (XP SP2, 2 GB of RAM, 2.6 GHz P4, plenty of available storage space). Never had a crash with any version of LR (released versions), with a single catalog of about 30,000 images.
What's your system info?
I'm on an iMac G5 (for about one more week before my 24" intel iMac is ready).
I never lose any data, escept the last step. It usually happens after that weird slowdown LR is experiencing after a while, and then usually when moving the exposure or white balance slider.
Actually, the move from grid view/library to develop got much faster with 1.2
The other way, from develop to grid, takes three to four seconds.
This might be, because universal binary software runs on both PPC and intel processors, but is optimized for intel, and therefore possibly slow on the G5.
I'm mentioning these issues as a point of discussion. I love Lightroom and using it is the sheer fun.
As software as young as LR always needs improvement, and discussing those points can only be helpful.