Tough question. "Good shape" to some people might not be the same to others. For example, are you experienced enough to know when a monitor looks like it's in good condition?
The fact that it resets itself is a problem. If it didn't have a problem I'd say you got an "ok" deal but on the high end. but the fact that it's defective makes me think you got a little ripped.
I'm sure others will pop in here and say you shouldn't have paid more than $200, while others will say they sell on Ebay for $600+, so who knows.