I don't know what the exact differences are. The list/display is definitely different. I'm hoping that the newer roms at least handle team cricket better. On mine (version 2.0 or 2.1) each player on each team needs to mark each number 3 times (6 marks per team) for that number to close. In the leagues I play in, teammates work together on each number and each team only needs to mark each number 3 times to close that number. Another thing is how my board handles averages, in 01 it does a round average, I'm used to a per dart average. My machine is home use, and I use it to practice. Being a practice board, none of this is high priority, but if a few things are handled better, I wouldn't mind upgrading. There isn't a whole lot of information readily available as you've said, but the price you've mentioned is pretty much right around the ball park of what I was expecting them to cost. I believe only 2 roms will have to be swapped, U7 and U8.
If you want to put up a list of games available on your roms, I'll do the same for mine later this evening. Maybe we'll be able to find out a few more differences.