DAA - When looking at Remington barrel spec's you need to read closely, I know I did anyways. Many cantalever barrels are rifled, but many models are not, they come with a rifled CHOKE and a cylinder choke. If it doesn't say FULLY rifled it is a remchoke with a rifled choke tube (a quick note to Remington confirmed that before I ordered). The slug barrels, like the one I purchased, are the same. The sights are fierce too.
I looke very hard at the cantalever barrels and was about to make the jump, but read a review on Midway that said that the base was aluminum and the guy bent his a couple times. Made me nervous. If the pictures of my shotgun are still available (occasioanlly they go away for some reason) you can see that I went with a weaver side mount. The reasons are two fold. First the base is absolutely ROCK solid and very low to the receiver. Then I like the fact that the scope can be easily removed. A good option if the scope looses battery power or you need to take it off for any number of other reasons. I like the mount very much. There is a negative though. You can't mount a side saddle shell holder on th receiver. Mine is mounted on the stock, but the jury is still out on that, because you simply can't shoot from the weak side with this shell holder in place.
The stock I used has surprised me as well. I'm not an AR guy, you probably know that, but this stock arrangememt is becomming more and more comfortable all the time. A side advantage. This 870 was brutal to shoot with heavy loads, I don't know why, but it was awful. This stock has tamed the felt recoil significantly and it's not one of those designed to do so.