There are a few misleading statements that should be addressed. First, one advantage the Spartan has when making performance claims is that none are actually operational - it is a developmental aircraft (one of those "paper aircraft" that MND keeps talking about). For that reason, it is difficult to confirm or deny performance figures. Also, when you post data to compare aircraft, probably best to post data only from the site that makes the aircraft - the competitor may not have accurate info. For example, the C-295 is not fitted with an APU, but it is an option - that detail will not be included on an Alenia website.
The issue of C-27J commonality with the C-130J is now pretty well limited to the propellers. The engines are smaller and lighter than the 130J, with the multi million dollar upgrades made to the C-130J avionics and software, the cockpit and software commonality "advantage" has vanished. Both the C-27J and C-295 can handle a Hercules Standard (108 x 88) pallet (loaded 98 inches high) by turning it 90 degrees and reducing the height of the cargo on the pallet. The difference is that the Spartan can handle 3 pallets loaded 80 inches high, the C-295 can handle 5 pallets loaded 60 inches high.
The C-295 is FAA certified, the Spartan is not, and the G-222 was not. The CN-235 has Canadian certification. The CN-235 and G-222 history is important, because the two newer aircraft are just re-engined (and modified) versions of the basic aircraft. The structural advantages and disadvantages of each will remain. One of those problems for the Spartan is a high stalling speed - about 10 knots higher than a Hercules with the same SAR load and equivalent fuel endurance. Unfortunately, that is a safety issue for the crew when dealing with mountain contour search, as well significantly degrading the effectiveness of search - the faster a search aircraft goes, the less the spotters see.
The Spartan did not just have water leaks around the windshield on the Greek aircraft, the problems that the Hellenic Air Force encountered included alignment problems with engines, propellers, and landing gear. They are holding payment until the problems are resolved, but did agree to let deliveries continue.
Finally, the Spartan or G-222 has never been used as a search aircraft or Maritime patrol aircraft - which means that the type of problems currently being experienced by the Cormorant (grounding due to corrosion, parts and serviceability issues, and lack of integrated EO/IR capability) should be anticipated by the launch customer for a SAR version. You can ask the SAR techs in Trenton how they are enjoying their Cormorant, but you better duck after you ask - they will not see that aircraft again for at least a couple of years. Instead they are "making do" with Griffons, because the effort required to take the Cormorant to full mature status has resulted in an availability that is a fraction of what the manufacturer claimed, so Trenton gave up their aircraft to the Coastal squadrons.
The bottom line is that the project office has not written a SOR based on SAR requirements, they have written it based on the specifications of the Spartan. That is contrary to Canadian government procurement policy, and does not do either taxpayers or SAR crews any favours in the long run.