In the last 25 years I have only sold one game, and it was GB pro. I purchased it NIB and it did have 1746 plays on it when I sold it.
The game can be fun, but can also be not so fun. Hell one game may last 5 minutes, then the next game you get 5 extra balls and all kinds of stuff.
Totally out there, but the reason this game was no longer wanted to be played by me or my girlfriend was because we had a damn awesome dog adopted from the pound...best dog I ever had, and every time the game said "ok, who brought the dog"? he would show up and we would laugh. At only 3 years old a coyote got into my fenced in yard and killed him. Very damn sad. But also my gf took all that a whole lot worse than I did, and you know what happens if you don't keep a gf in a good mood...so GB was the hell out of here!
I like ramps on pins, and to me MET just feels so awesome, best feeling ramps on any game. And Sparky is just too damn funny. The first time we ever had the Sparky MB the game said "Fry That Mother f____er".
But, with all that said, like others here have said, there most likely will never be a shortage of used MET or GB for sale, so you can buy and sell and go back and forth. And hell, Stern will probably someday do new VE editions of both also if you want NIB.
And maybe by the time they do a VE all the playfield pooling and chipping issues will be cleared up.