IMHO TS2010's (44088) been the most stable for me. Really enjoyed TRS2006 before TS2010 came out... (4+ years with 06).
Foot note; Give me "most of" NV3's, Pofig's and Mcguirrel's speed-trees over cardboard cutouts any day... I guess at the end of the day, it's up to each individual as to whether they like, or prefer 2D trees over 3D trees...
I think big improvements have been made in the development of speed-trees since NV3's initially launched them. Hopefully they will continue to be a "work in progress" and be improved with more variety available over time...
Cheers, Mac...