I tried on the new Jumbo recently and it was absolutely amazing. A perfect sport watch on a bracelet. I would choose it over the 15400 and the Patek without hesitation (and I love the Patek too)!
I have a blue dial 15300 and am quite happy with it. The quick set date, seconds hand and larger size differentiate it from the Jumbo. There are plenty of brushed surfaces which, to some extent, de-bling it. The Nautilus is certainly beautiful, though the case lines and combination of finishes on the AP have lessened my craving for one.
I've been down this road many times. I had a white 15300 (well before 15400 was available) and the 5711/1a at the same time. Th 15300 is very nice but the PP felt more "special" to me. You can't just base the purchase on looks alone. Ask yourself if you bought an AP if you would still be longing for the PP. Answer for me was yes...went down the PP route and never turned back. Get the PP if $ is not an issue but I agree with some that the AP is better value is you're just comparing watches.
not that I don't like the AP's but after owning several Offshore and having a 5980 I can tell you one significant thing .... the AP's bezels are very sensitive for dings and scratches and you'll hate it for that after a while, I have my 5980 Nautilus now for more than 2 years and it still looks like new because the edges are far less sharp than the RO which makes it less vulnarable !
Assuming the price isthe same, I would still be in favor of the Nautilus.
Clearly Genta had a vision for a sports watch that manifested itself in the Royal Oak. However, the design of the Nautilus for me shows an evolution of the port-hole theme that is more resolved. The lines of the Nautilus case are cleaner and more fluid. I also find the Nautilus dial less busy than the Royal Oak's tapisserie, the batons are also more defined & stronger.
The negatives for me on the Nautilus are the bracelet is a bit showy, I'm not sure if I need such a refined movement, and yes, there is some stigma with owning a Patek
To me the Royal Oak is a bit like the Porsche 911E while the Nautilus is the 993, both are awesome pieces.