I'm a bit on the pessimistic side when it comes to purchasing anything via the internet. Especially
ebay. And the problem with asking that question about good dealers, that too is rather a possilbe risk. The reason is you don't know who is doing the recommending. Well may be an employee of the dealer they are bragging about. Then too many blurt out the name of a dealer with no or very little actual, personal experience, only what they heard from someone that heard it from someone. I really would ignor suggestions about great on line dealers from people you don't know. They really have nothing to loose if wrong.
One of my problems with dealers or almost any organization is when new, many have great deals, fantastic prices, wonderfull services. Then as their buisness grows, some or most of this vanishes since now they know there are many others out there that may buy, buy, buy.
I've seen this with coin stores in my area over the years. Also, with grocery stores, furniture stores, department stores, etc. Possibly one of the many reasons so many go out of buisness.
My usual suggestion is to try to find coin shows in your area. If there are any, go there. Also, check for coin clubs in your area. And of course members right here. I don't think I've really heard anyone complaining about a deal with a member on this forum.