You really can't talk about "the" plastic ball since there are 3-4 versions that are quite different from each other and from celluloid. There are currently 5 factories in the world making plastic balls, 4 of which have brought balls to market that are ITTF approved.
Two factories are making seamed balls in China (DF and DHS) and sold under many company's names, including every major European company (unfortunately). Seamless balls are made in China and sold as XSF, Yinhe, Nexy, Stag, Palio, and some others. And the Nittaku Premium 40+ are made in Japan (and not to be confused with the Nittaku SHA, which is a re-branded DHS).
All are somewhat different. The ITTF-approved versions of seamless balls and the good Nittakus play reasonably well and are not hard to get used to, but the others until now have been complete garbage (but maybe there is some hope that this will improve).
All 40+ balls have somewhat reduced spin and speed compared to the 39.5 mm celluloid balls we were using before. All of the plastic balls have a rougher external surface as well, which causes the ball to jump more in response to sidespin, and to sit up a bit more on pushes. All but seamless have had durability problems up to now. The Chinese seamed balls bounce quite low and IMHO are very hard to adjust to. They are the least durable in general, and they have the highest percentage of deviation from roundness, which I think can occur after a hard hit to the table. This doesn't happen with seamless because they will just shatter on the rare occasions when they break. Nittaku Premium balls are less than 2.70g, seamless balls are around 2.73-2.76g, and DHS-made balls are almost always over 2.80 g.
I have come to prefer the seamless balls and the good Nittakus to celluloid, mainly because it's all I have been using for last 9-10 months. I still hate the Chinese seamed balls.
So my answer to your poll is yes (seamless and good Nittaku) and no (everything else at the moment).
It is a problem right now that we have so many ball variations in legal competition. That situation I vote big NO!!!!!!!!!!!!!!! The increased price is a problem. And only the seamless balls are highly durable. Finally, Nittaku Japan balls have major availability problems.