What's frustrating about both new R2's - HT and Tama - is that more than improved finish/realism, I was really wanting an R2 that was bigger in terms of girth and also a bit in height over the Sideshow R2, which always feels a touch too small (mostly, thin) on display. The Sideshow diameter is around 2 15/16" and unfortunately both the HT and Tama seem to have come in around that - the HT maybe being 1/32" bigger than the Tama, but both at the same 'a hair under 3"' mark that the Sideshow is.
Even though these new R2's are truly incredible detail and finish-wise and a noticeable leap forward over the Sideshow, to me, the Taito clock (unfortunately, with its low-end sculpt detail and poor paint apps) is the only R2 figure that seems about right in terms of girth and overall "size" for R2 - it measures at a little over 3 1/8" diameter. With corrected feet (the Taito foot sculpt is missing the lower tread portion) it's maybe a 1/4" taller and a 1/4" wider than the Sideshow.
There does seem to have been some size variance for the screen-used R2 builds depending on what it had to do onscreen, and supposedly the ESB and ROTJ R2's were rebuilt slightly smaller than the ANH versions, so I guess I'll just have settle for the smaller of that range.
I'm planning to customize the Taito I have to be quite weathered to cover up the poorer sculpt issues, but I have a feeling he's the one I'll be partnering up with my Tama 3PO, not the HT or Tama (I'm getting whichever I can get the best deal on) which I'll use for a "centerpiece" display on his own.