I plan on getting one after my car gets out of the paint shop.
I read on another thread here recently that you shouldn't top them off full since there's no expansion tank inside like the originals had. They'll overflow out the filler once it gets warmer than when you filled it.
This is accurate. I have a Spectra tank, no real complaints, its a good quality tank. But I did notice that if you fill the tank completely, you'll end up with fuel in the vent lines (on cars with carbon canisters). My '71/'72 tank has the 4 lines on the side, the hoses that go out to the vents etc do end up with fuel in them if you really top off the tank.
But, given the way that the gas station nozzles here in CA work with the filler its not the best idea to top off the tank anyway, since that usually leads to fuel on the paint at the filler too.