I would download v1.05 RC2.It is the most stable version I have found IMO.
You can search the Product Chat forum for the various threads that will tell you more about what the upgrades do.
Some of the cool stuff:
Save/load
fog
If you remove an entity/segment from the map when you save/test build your level it removes the entity/segment from that level...
i.e. no more worrying about having a bunch of stuff in your level that you don't want.
Lightmapping improvements.
Some scripting commands have been added and now you can have dula wielding weapons (although Butters could do it before with v1).
Welcome back.It's good to see you are back around.You have been missed.