Well guys, I gotta recant my earlier post about no issues.
I decided to try those 3D titles listed and had the same stuttering you mentioned - BUT only on the PS3. Immortals and Tormented were no problem, but every single title Sinistar listed was a problem. So I chatted in with Netflix support. They said that they would like to hear from guys with higher speeds than mine that can't watch these 3D titles.
SO PLEASE chat or call Netflix. They really couldn't help me saying that my speed is not fast enough to expect 3D titles to play well. HOWEVER, my Sony TV's Netflix app plays them ALL just fine, but not my PS3's Netflix app.
And before you ask (as Netflix asked) my PS3 has plenty of memory, is up to date and is only 2 months old. Same as the TV. The TV's web apps all typically perform MUCH worse with lag and buffering than the PS3's. BUT the TV will stream 3D titles that the PS3 won't. ???????