The update 3 is the most stable on my machines. It is still very very slow unfortunately.
LC 10.1 beta appears to be a bit quicker but still extremely slow. The beta is also not that stable which is probably why it is still a beta.
The only thing of importance that has been added is the color temp slider. Now if I just knew what would be neutral with the tint (green/magenta) slider it would be really useful.
To be frank for such a long development time so little extra features and so litle implemented of the stuff that was on everybodies wishlist is disappointing.
I now use RD for basically all my RAW processing with Leaf files. Truly fantastic. I use LC10beta or Update3 for tethered shooting. No more LC8.
I have kept the firmware of the the beta version in my back. I do like the bluetooth on (even if I cannot use it yet

). I don't want to have the software update my firmware back and forth every time I switch between 10upd3 or 10.1 beta.
I would not be suprised if 10.1 will be skipped and Leaf will come with LC11 instead. There is way too much negative connotation with LC10. No software, how good it will ever be will flush out the bad taste LC10 has left with many.