Dear friends all of you: IMHO this tonearm subject is a very controversial one ( for say the least ) and very complex. Here in México we say " everyone talks like goes on the fair ".
Some way or the other I think that everyone can/could be right, IMHO there is non absolute answer to the subject only relative answers.
From pure theory ( and only on tracking error subject ) there is no doubt that a LTT is the best way to go like from theory a 12" pivot tonearm is better than the 9" one, but tracking error/distortion subject is only one of several other same importance level subjects than the tracking distortion.
Why a tonearm ( it does not matters pivot or LT ) performs better than other is the summary of several different parameters ( other that good cartridge match and set up ) that help to top quality performance or that contribute to a lower one: bearing design, bearing type, bearing tolerances, bearing material, bearing friction value, geometry design/choose, tonearm length, build material ( whole ), internal wiring, effective mass, damping type, design execution, etc, etc, etc, all these " parameters " and many others help to define the tonearm performance.
I have experience on tonearms over the years not only with pivot ones but LT too ( including the ones from Rockport/Walker ). It is true that the LT are something special ( specially on soundstage that it is not my top music priority, important but not critical. ) but the pivot ones too specially on both frequency extremes where IMHO no LT surpass them.
IMHO too there is no perfect tonearm design, pivot or LT, the best one is the one that match your trade-offs/music priorities.
In the last two years ( maybe more ) Guillermo and I were in deep whole tonearm research looking/building for a Universal tonearm ( the perfect one ) where we already made several live tests ( with our tonearm prototype designs ) to be near that almost impossible target: Universal/perfect tonearm.
We try 12",11",10",9",etc, etc and about tracking distortion I agree totally with Cjfrbw: you can't hear the differences at least differences that you could say: hey that is because lower tracking error!, no way. As imperfect is the playback analog rig as imperfect are the analog recording process and these facts preclude that the theory is on command.
. Btw, when we talk about lower traking error between a 12" tonearm against a 9-10" one we are talking of 0.8 degrees or less, with all respect to all of you : no one can hear it. The special soundstage performance on LT is more a result of its non mechanic grounded bearing that of the LT design.
IMHO it is more important a good execution design, cartridge match and good set-up that pivot vs LT subject.
Guillermo and I choose a pivot tonearm design over LT because we think ( maybe we are wrong ) that can/could be nearer to the Universal tonearm, we are really exited on the quality performance showed on our last prototype: very promised, we will see over the time to come.
Spl, don't worry about which is harder to set up properly there are many other more important subjects ( of course that a friendly set up is always desired. ) to choose your tonearm.
Regards and enjoy the music.
Raul.