I believe the seller's name is Randy Therm. I have purchased a few items from him over the years, but have not followed him closely and I do not "know" him.
His offerings appear to be generally solid, however it's always best to ask about a specific item if that is what you are interested in.
It's Randy Thern out of Wisconsin. He is honest. Been in business many years. With that said, you will still need to verify his autographs just like everyone else.