Yeah, if you are happy with v2, then you could hold off on buying v3, but the general consensus is that v3 is 'the one', where everything starts to just work, including FSX's old memory issues.
And v3 is still a work-in-progress, so it might even get better. But the way their licensing works, it can get expensive to go with every major version change.
EDIT: I just went from here to Avsim,
and saw this post. There are a lot of posts like this, and I don't really recall seeing this sort of thing with any previous sim/version.