I've had a couple of Grizzlies (still have my bead sight 12.5") and a buddy had the mag-fed one. He told me not all the mags ran perfect, but the problem ones took little to get running perfectly. (he didn't elaborate, I didn't ask) I've had lots of 870s come and go, still have a couple...but I do dig the Grizzlies. Heavier than they should be, a little rough around the edges...but fun guns for the $ if you ask me. Like the SKS of the shotgun world~you could show a new shooter a Citori, a BPS, a Wingmaster, a nice Benelli, a Grizzly...guess which one they'll want to shoot first? lol
What to replace? The furniture isn't great, but functional. The forends I find to be a bit slippery no matter what the conditions, with or without gloves. A Hogue is a very nice improvement for $25