EVERY time I test one of the third party up-rez products, compared to Photoshop out to print, I come to the conclusion that I'll stick with Photoshop. Its always faster and of course less expensive. To output, the differences are often image specific and very, very, very (that's three very's) subtle to the point that I don't think anyone would prefer one over the other at anything even remotely close to viewing distance.
Don't compare the products based on what you see on screen. You really need to print the comparisons out. If you want to put your nose up to each print, fine. From viewing distance, half viewing distance, you'll never see the difference.