Sorry, but I have to disagree with this as a current appraisal. 90 percent in a stainless gun is a whole lot different than 90 percent in a blue or nickel one.
Are you new to firearms in general? If so then you are likely under-estimating the gun. 90 percent is great on a book report or free throw average, but not so much on a firearm. Don't just call it 90 because it looks nice, picture the total surface area of the gun and subtract the portion that is not like new - don't forget to look under the grips as stainless can and will rust. Then do a mechanical check for timing (carry up), lock-up, end shake, cylinder gap, crown, and push-off. Inspect the bore and chambers next. You may find it better than you first thought. If it is only cosmetic flaws such as burnishing or polishing of the high points, that can be addressed.
The 625-3 in four-inch is a highly desireable and practical gun. I highly doubt you will find many, if any, under $600 or even $700 unless they have been irreversibly modified.
Your dealer offered you a fair deal and if you want the gun, I suggest you call him now and take it. Don't believe me? Run a quick check on Gunbroker.
Deals and steals are great, but don't get in the habbit of holding your breath for them or you will sit empty handed for a long time. Buy once, cry once. You will get your money back if your don't like it.
Tell you what, if you decide to pass, PM me the name and number of the shop and I will put my money where my mouth is - I'm not kidding.
Good luck.
A.