I own a mossberg 715t, my brother has the regular mossberg tactical with the carry handle. I've fired 5000 plus rounds from my 715 and my brother is probably at the 2000 mark. If your set on getting a mossberg get the flat top, the sights are WAY better and more adjustable, other then that I'd say his and mine are both the same. My mossier groups 1-1.25 moa at 50 all day long and stays reasonably accurate out go 80 yards or so. It was a little ammo picky at first but now it eats any ammo I can shoot through it. It takes me like 2 mins to break it down its really not as bad as people will lead you to believe.
My friend lent me his 10/22 with the marauder stock on it. I had the pleasure of doing a back to back comparison over about a 2
week period. I found his 10/22 to be very ammo picky, with lots of FTF's, I tried 8 diffent kinds of ammo with pretty much the same results. I'm not saying this is the case with all rugers as I've only played with the one 10/22, but I was let down cause all I'd ever heard from people is how superior the 10/22 is to my mossy. The ruger grouped about as well as my mossberg so accuracy was the same.
As for the marauder stock, I would never buy one personally. The stock is very well built and sturdy, it's twice as thick as my mossberg. The sights are terrible, and you need a Allen wrench to adjust them

. I found the marauder stock to be almost as much work to take down as my 715. The length of pull is way to short for any adult, it lacks the adjustability of my mossberg.
To me if a guy only wants to spray and pray then the marauder is a great toy and is a lot of fun, but for target shooting it sucks unless you want to mount an optic of some kind.
This is only my opinion and you know what they say about opinions!! I'm not a mossberg guy by any means I'm just going by my own experiences with the 2 guns in question. My favorite .22 in my safe is my wife's $139 marlin 795. It's cheap never has jammed in 1000 rounds and shoots 1/2" or better moa at 50 yards. It has a bypod and scope and we're still only into it for around $300.