First, let me echo the chorus that SR needs its own official miniatures line. I am sure that the fine folks at Catalyst have a lot on their plates, but I strongly believe a partnership with Reaper or another established manufacturer would be an awesome alliance.
Second, on the older Ral Partha line: some of the figures remain usable, but the majority suffer from a number of issues. Scale is a big one. They're 25/28mm when most modern minis have "evolved" up to around 32mm, and the differences in aesthetics are noticeable. Another issue is availability--they're not readily available in the distribution chain, and certain minis can only be had on eBay. Finally, and most important, the style of the game has moved on from these minis. Hackers aren't deckers. Firearms have changed. Hell, even the fashions exhibited by the characters in the SR4A artwork look markedly different than the old line of minis.
Don't get me wrong--I love them, but they are quaint. I still use more than a few of them in my games, but SR4A deserves a slickly produced, modern line of miniatures. I think Randall and the crew know this, but they're likely very busy as is, so we must wait. In the meantime, I'm still running games and I need minis, so I scratch together what I can. If you feel so inclined, please check out my blog for some of my musings on SR4A and the miniatures I am using to run it.
Here's a handy link:
http://four-color-figures.blogspot.com/search/label/ShadowrunThanks for looking!
--S.
