When I originally saw this thread I didn't realize we were talking about different bikes with different suspension platforms. I'd do more research on the suspension kinematics of each design, for that will have a much, much more significant impact on the way a bike rides than the individual components. In other words, if for whatever reason you don't jive with the bike's suspension platform, upgrading every single component isn't going to make it more enjoyable for you.
There's not much info on Fezzari's site about their suspension platform except for a crude leverage curve, which looks very progressive, but it doesn't include leverage ratio values on the chart's axis, so who knows how progressive it is. This isn't necessarily bad, but something very progressive mated with an air shock might make it difficult to reach full travel. Especially if you're a lightweight rider.
I can't find a leverage curve for a current Giant Trance, but what I'm finding is that most Maestro leverage curves are progressive, but not nearly as much as the Fezzari. The Maestro curves also have a different shape, in which the rate of progressiveness decreases as you reach full travel (which in my experience is good), as opposed to the Fezzari in which the rate of progressiveness seems to increase as you reach full travel (which will only make it more difficult to reach).
Not that all of this is necessarily any help, but as someone that has ridden lots of different suspension platforms I thought it was worth pointing out.
But, honestly what it really comes down to is this:
