As someone who alternates between 100% RP and 70% RP (as in, I will always be a heavy RPer, and will RP every character I play), I've got no real reservations about using a non-RP Free Company. I know a number of the people in the Free Company are RPers, the officership specifically, so I'm not worried about not being able to use the FC house for RP. Though Unity won't be an IC group, we will still be RPing with one another, and I'm sure we'll be using the FC house as some kind of IC gathering place.
I also know that Unity has skilled PvEers, and I personally wouldn't want to attempt doing PvE seriously without the resources the Free Company provides. Especially not the scale of PvE that ARR is going to deliver. I think one thing to keep in mind is that, while Unity is open to casual and hardcore players and everyone in between, there's going to be a core of very progression-focused PvEers. I will be one of them, even as I RP very seriously on a (hopefully) daily basis. To me, the resources of the FC are integral to that.
I also know that Unity has skilled PvEers, and I personally wouldn't want to attempt doing PvE seriously without the resources the Free Company provides. Especially not the scale of PvE that ARR is going to deliver. I think one thing to keep in mind is that, while Unity is open to casual and hardcore players and everyone in between, there's going to be a core of very progression-focused PvEers. I will be one of them, even as I RP very seriously on a (hopefully) daily basis. To me, the resources of the FC are integral to that.