If you think you need it, buy it.
I don't see much of a need myself.
I don't like ProChannel or it's add ons. I prefer the sonitus EQ to anything in PC.
The only compelling reason for me to get X3 would be if I didn't have Melodyne.
I got X1 and I think X2. (I forget).
- What can it do better than 8.5? nothing.
- what does it screw up that I have in 8.5? lots.
I think X3 is targeted at those that don't have all the extra software toys that go with making music these days.
If you don't have that stuff independently then maybe it's a good buy. I would say buy the quality extras you need instead and stick with 8.5. But then, time goes by, and with it any upgrade curves and falling out of the loop per se.
Just some random incomprehensible thoughts.