I'm sure there have been discussions on this and if so can someone point out a link. Would anyone consider this as a must buy option for a new receiver.
Hmm 6.1 or better I consider as a must buy option.
DPLII would certainly be a must buy option for me, and I would assume if I was buy'n today, I'd make sure DPLIIx was included, but I may not go so far as to say it is a must buy option though.
DPLIIx would be useful if someone had a 7.1 surround setup. If you have either Harman/Kardon or Lexicon though I find that Logic7 is a little better with TV programs and movies while PLIIx would probably be the best choice for music...
I have only heard PLIIx one time for a brief period and know very little about it so don't take my word it's capabilities.
i would say it depends on your personal preferences. if you are interested in 6.1 or better, then the answer is IMO a clearly yes.
consider, that dolby pro logic2 is basically a *matrix only derrived* 5.0 format, which was developde for 2channel sources only. now dolby pro logic2x is a 7.1 format which works for two channal sources AND for discrete 5.1 sources as well.
personally i never was and never will be a friend of those 6.1 formats like dolby digital(ex) and dts(es), since in my opinion the limitations of one or two (monophone) backsurround speakers are far more to concern, then the *advantage* they pretend to deliver.
with the two backsurrounds running in stereo on the dolby pro logic2x format, those limitations will be overcome, similar to that, what the lexicon processors have been doing for years with their own logic7 technic (to my ears the absolute best surround format so far).
so if you have plans to go beyond a 5.1 system, i'd say it is REALLY a must have feature.