There is an old saying, which I have found to be very true. Buy cheap buy twice. Unrelated to coins, I had a bathroom remodel. I went on the cheap side, paid a few thousand less for a guy that was eager and not as busy. Work got done, quality acceptable. However it turned into a 12 week job with a lot of delays, frustration and having in the end to call in real professionals to finish the job. In the end I would glady have paid more for a well rated costlier professional.
However, tangential that philosophy applies to coins. While the big houses can sell fakes, as no one is perfect. They will most likely be there a decade later if the coins proves to be fake. This especially proves true for those of us wanting to acquire top rated and top notch coins. You will not find a coin like the Hadrian I acquired from CNG on
ebay, in all probability. The simple reason is money and cost to sell it. Ebay/Paypal charge sellers close to 15 percent to sell. A large auction house like Heritage charges between 7-9 percent on a high end coin. Why would anyone sell a ten thousand dollar coin on
ebay, when they could pay half the commissions to the larges auctions house in the U.S? I have found high end auction houses willing to charge 4-5 percent for coins over five thousand so doing it on
ebay is not the most profitable.