That is a fantastic progression of skill! They are all very well done (old and new) and capture McQuarries images well. I like the detailing on the new Threepio. I think perhaps the older one is truer to McQuarrie's proportions, but I like the more masculine proportions of the newer one.
Do you sculpt all of the parts? (on the Steam Punk and '42 series as well?) or do you start with some base figures and embellish?