So, with like 9 days left on my V6 trial (and another cover I'll hopefully finish before the 9 days are up), my consensus on it:
-Haruka and Akito are good, but also sound like Meiko and Kaito without the charm or character
-I LOVE Sarah and Allen though, they are the best new Vocaloids in a long time
+For that matter, I'm glad I never bought SynthV Natalie because Sarah is the kind of vocal I actually wanted. Natalie sounds so lethargic in comparison.
-The V3s and V4s sound good in V6, but chances are I'll continue to use them in Piapro (I'm just more used to that one, plus I like the interface. Even if I switched to using them on V6, I would still need Piapro anyway for my V2s and my Haku configurations relying on the old BRE parameter)
+And V6 is kinda hard to tune in but I'll figure it out as I go on using it. I've already figured out several functions to make tuning go more smoothly in the weeks I've had the trial (like one tip, the pitch bend parameter is quantized like the notes by default (just like in Piapro Studio))
-I'm basically buying V6 to continue using Sarah and Allen, but I'm also looking forward to future V6 releases and having the V5 starters too (even if once again I only use the English ones)