ZT1 is still my favorite pastime. I like its detail and its educational value. Those are what got me interested in it in the first place. But being a programmer, what has kept it my favorite is the ability to add things to it in almost all categories. We continue to find new ways of doing things with it. I have tried all of the ZT2 demos and have watched others play with the full version, but, for me, it isn't as realistic as ZT1 and seems less flexible. Sure, there are some very interesting things that ZT2 can do that I wish ZT1 could. But it is usually the other way around.