I'm a long time Checkpoint user, and new-to-PFSense user.
The PFS unit will not be swap-replaceable with the CP unit, without doing some setup at the remote end.
Typically, the main HQ controls the "enforcement points" configurations remotely.
They "push" a configuration file that syncs all them together, so if you swich out the CP unit for PFS, I suspect you'll be getting a phone call from HQ when they don't see the CP unit online anymore.
You'd need to co-ordinate with them, and they will need to create a new "compatible device" at their end with the parameters of your PFS unit for the VPN tunnel(s).
Be careful about NAT-T. CP handles that well.
PFS, well in the next release (R2) it should.
1.2.3 - not so good.