MarQueis is a nice pickup for the Vikings, I was really surprised when the Browns cut him. Due to Manziel mania, I was able to see a number of the Browns preseason games and MarQueis was running with the first team often. I thought he was the Browns best offensive skill player in at least one game and he showed very nice versatility in lining up in the backfield and catching a pass on an out route and then on another play he lined up on the line and got open down the seam (and Tyler Thigpen hung him out to dry with a high ball that ended up with MarQueis being checked for a concussion).
On the negative end, I saw the fumble he had in the preseason, but I didn't feel like it was particularly terrible. It happened near the sideline as MarQueis was going down, the defender hit the ball with his helmet (if I remember correctly). It was more of a tough play than a sign that a player is fumble prone.