A slightly different opinion
While the Encore will handle larger rifle calibers that the Contender/G2 cannot, my opinion is that you would be better served from a handgun perspective by the Contender.
Considering what you can actually get out of the (at most) 14" barrels, I don't think getting an Encore in a large rifle caliber is worth it. You get to spend a bit more money (ammo cost) for very little benefit. You will get a few fps more from the bigger rounds, but at the cost of increased blast, recoil, and cost for a very small performance increase. Now, if that matters to you, then go for it, but other wise, why bother?
Remington brought out the .221 Fireball, specifically because they could not get full performance from the .222 Rem in the 10" barrel of the XP-100 pistol. So they went to a smaller case, so that there wasn't as much "waste".
All the powder you burn outside the barrel get you nothing except blast, so why waste it? Now, if you already have rifles in those calibers, then that is a reason to get an Encore, but otherwise?
I have a Contender (an old one), and about a dozen barrels, most of them 10", with a couple of 14"s. That's plenty for me, because when I want a more powerful round than the Contender handles, I want a rifle to use the long barrel to get the most from it.
If you plan on using your pistol as a rifle also, then the Encore makes good sense (remember, under the law you can put a rifle barrel and stock on a pistol, but you cannot legally put a pistol barrel on a rifle action and use it as a handgun) because your can have both pistol and rifle length barrels in large calibers. The Encore in a full size rifle would make a dandy carbine length package, while keeping the velocity advantage of a rifle length barrel.