Ken,The Nitro-Piston rifles will provided a smoother firing cycle and typically give you more power than a spring piston air gun. Also, you don't run the risk of compressing the spring if left cocked too long when you are using a Nitro-Piston because there isn't a spring to compress (I know the Regal is a Nitro-Piston, I just thought I would mention that in case you weren't aware of it). As far as whether the All-Weather NP is better than the Regal NP... I don't know. The All-Weather stock will most likely be more scratch and weather resistant than the wood stock. I would read reviews on some of the websites that specifically sell air guns and nothing but air guns.Concerning your groups with the Trail NPXL 1100, that second target does look much better. It definitely takes time to get the hold down for that rifle and figure out the trigger too. Eventually (especially if you repace the factory trigger with the GRT-II trigger) you will get those groups to be 1/2" to 1" at 20 to 30 yards and better once you've got the rifle figured out. The NPXL1100 is a heavy gun. Most of that weight is in the action of the gun (compression chamber is really heavy). It is a real fun air rifle though and you will undoubtedly get quite a few critter with it.One thing to mention... I know in the manuals is says to oil the parts in the compression chamber, but don't ever do it! You'll end up blowing your seals and have to have it repaired. The seals and rings in most modern air guns are self-lubricating. You can grease the pivot joint where the barrel breaks, but that is about all I would do. Maybe in 2 or 3 years you can put a drop in the chamber (a very, very small drop since it doesn't take much) but even then, if the gun is shooting good, don't mess with it.
.Let us know what you decide to get instead of the Regal NP.