If its a choice between the Gamo and the Quest, stick with the Quest. The Crosman crowd loves them, and they seem to be fairly decent out of the box. It seems to be one of the better Chinese guns.
The new Benji guns seem to be of lesser quality than those made in the past, and they seem to have had more than their share of problems lately, especially with barrel production. Also, no longer do they have walnut stocks, but rather some sort of generic hardwood with a crummy varnish finish. Most owners also find the trigger to be awful, and all that pumping can be difficult for the unaccustomed in an extended shooting session. I have a late model 392 and 397, and I wouldn't reccommend one as either a first gun or a trainer. A gun that is inaccurate and/or hard to operate and isn't made well can easily discourage a beginner. A bad first experience can be hard to reverse, and if he really doesn't enjoy the gun he may not want to shoot it anymore.