Maybe instead of comparing the super puma to a 14'R, you should think about a Super Duper Puma.
We have a super duper puma and a traditionally sized round 14' boat. I agree with most everything above, but you might want to consider the SDP instead of the SP to a 14'R.
The super duper puma is plenty big to take on self support week long trips with 2 people, or about 2 night trips with 3 people packing lighter. If you plan on regularly doing more than 1 or 2 nights with more than 2 people get the larger 14' round boat. If you plan on doing short and occasional overnighters, but mostly day paddle trips get the SDP. One thing I really like about the SDP over the larger 14' boat we have is that it far better on low, and tight/technical creeky runs, which is my preferred type of run and on steep technical, and I can actually pick it up myself and move it around (just the boat without any gear) loading it in the truck etc. couple shots of the SDP fully loaded for many nights, handling class IV well with this load. I have a fairly low center of gravity when packing this SDP (drop bag, rocket boxes in the cockpit, shorter wider dry box, and relatively lower rower seating position), which makes it pretty stable when fully loaded, even in bigger water like the main salmon (nose first though through the big holes!). Actually have yet to flip it loaded (knock on wood, or pvc?) after many trips with class IV.
my 50 cent