I just had a somewhat similar conversation over here:
https://www.mobileread.com/forums/showthread.php?t=42794
I gotta say, those tablet PC's are pretty nifty, and if you're doing a lot calculating/science applications, having the ability to jump from your PDF to SPSS or whatever other statistical program you're using would likely outweigh the weight issues that come with a full computer (at least IMO).
(And I say that as someone who really likes his DR 1000s quite a lot.)