A stock, a good red dot sight, a sling; a remote is nice, too
Super strong, reliable, solid, simple, easily upgraded with home made parts
Heavy, front mounted gas cylinder, velocity difficult to adjust, slow rate of fire.
The VM was one of the first semi automatics, and was built to last forever, which it will. Unless you actually put it on an anvil and hit it with a sledge, it will last as long as valves, ball detents, and o-rings are availiable. I just keep acquiring them ( I have four) because they are so easy to modify. I have made stocks, trigger guards, etc, for them. For a scenario player on a budget, you cannot get a more mil-simable marker. It is so massive you can drill and tap into it to add on all sorts of stocks and grips and make it look like virtually anything on the cheap. It has so many big strong screws going through the back of the frame that you can hang stocks and sights and such off it with little modification. Plus it already has the Lone Star grip of the M-16.
Even the front gas cylinder mount allows some creative action, since you can put a tapped stopper into it and a few elbows and hook your flex line to it, leaving more room for improvisation. Palmer's still has the rebuild kits, and unless your used VM fell into the hands of a primitive Pete mechanic who has stripped all the screws and shot it constantly while full of grit, you can restore it to like new mechanical condition easily.
I think that you simply cannot find a used marker for under fifty bucks that can touch the VM. If you are a low budget scenario player and a tinkerer, you can easily build something up that will impress the guys on the field, and with a good quality barrel keep up with the Tippmans yet.