Should repaired equipment be stated in the ad??

If it's repaired, there's nothing broken. What is there to report?

I generally agree with this. I think it's expecting a lot to have a policy of disclosure in the ad (and it's unrealistic to expect it to be followed). That said I think a request for service history (ie during negotiations) should be responded to completely and honestly. If you think it's not full/honest disclosure walk away (btw, A'gon DOES have a policy on this). Your description of the terse response you received is familiar to me - when I think someone is not answering the question asked I walk, unless I decide I'm willing to take a risk on a deal too compelling to pass on.

I agree with Macrojack in that most people on this forum are overly picking about equipment purchased here. It is "used" which means just that! You can't expect it to be like new. Unfortunately, some folks just don't get that.
As was stated when you buy something used, you're usually getting it 40% off of retail. If you want all this piece of mind and guarantees, then buy it new!! When you buy used you're taking a chance, bottom line.
My rule of thumb is manufacturer reputation and service record.(example: audio research equipment is known to be built like a tank and has a very good service reputation) I ask for serial number and then contact the manufacturer to see if the piece has ever been in for servicing. That's all you can do and even that is not 100% foolproof because if the piece was repaired by someone other than the manufacturer, you still want know, unless the person divulges it. If they don't, then that's the chance you take.

I would feel the same about a car.

People don't reveal repairs anticipating that somebody might be afraid of buying repaired unit. This person would buy something that has, what he considers, a hidden defect (loss of value in his opinion). The fact that they don't know about it doesn't change that they bought substandard (in their opinion) product. Therefore I would fully reveal nature of the repair and current condition and even sell for less if I have to (honesty costs).

There is a lot of factory refurbished stuff sold on internet with big discount. I believe that selling factory refurbished units as brand new is illegal but, according to many of you, factory repair doesn't change the value.

Can you honestly say that you would buy repaired one of two identical units sold for the same amount on Audiogon??
(everything else being equal). One person stated that repaired unit is even better - would he pay more? Seriously?

Serviced or repaired, I don't know,
But I'll take a Threshold amp upgraded by Jon Solderbreg.
I also prefer a car with full service records!