Recent experience with ASTG--positive, but know the risks
I recently completed an acquisition via eBay from these folks. It went smoothly, and really fast--less than a month from auction win to resort recognition.
As with any resale there are risks and things to be cautious about. I analyzed my risks and mitigated them until I was willing to go through with it, and there were no problems. This was a relatively low-cost (~$100) all-fees-paid acquisition, so my risks were basically (a) over-bidding/being bid-up, (b) title risk, (c) bait-and-switch risk, (d) risk of a delay/screwup in the recording/transfer, and (e) scam/Identity theft risk/getting my name/info on some list.
For (a), I minimized the bid-up game by using a sniper (admittedly not a perfect solution, but it does adequately). This seller did use the "private listing" method. Some here on TUG won't have anything to do with that, as it can allow sellers to bid you up as a single bidder, even with a sniper. I decided my max price using a sniper and took my chances. I got it for less than my max. Did I pay more than I could have? Possibly. Maybe if I had sniped at a max price of $5 I would have gotten it too, but I am satisfied with the price paid. Know your risk and bid accordingly.
For (b), they provided a (redacted) estoppel after I won the auction, everything looked in order--this was in a location with online deed search capability, so I was able to do my own title research. So minimal title risk there. Always a chance of a "fake" estoppel but everything hung together so I continued.
for (c), I minimized "bait and switch" risk by saving a copy of the original eBay listing as a PDF before I bid. This particular sale didn't have any paid incentives but did advertise free closing/transfer. I checked their draft contract and made sure everything matched up. I made two small adjustments/corrections to the contract which they accepted, and I used DocuSign to send all my documents, including the CC info. this particular listing didn't have any "follow up" type incentives such as free use or cash after closing.
For (d), I have to say they provided good communication, both the sales staff and the closing agent. It only took 11 days from auction end to get the deed recorded with the county. Then it took only 18 days more for the resort to process the transfer. The deed was recorded properly (except for a typo on the grantor's first name which was corrected) and near as I am able to confirm with the resort manager, everything is in order there too.
For (e), I listed only publicly identifiable information (my name and address is public record on other deeds) and paid with my American Express card. AmEx isn't perfect but they have some pretty aggressive fraud protection and resolution features I have been the benefactor of in the past, so I took the risk. If I start getting calls from them to sell back my timeshare I will act accordingly (just like I do with the ~10-20 other daily calls I get even being on the "do not call" list) and ignore them.
So, they worked out fine for me, and I gave them a positive feedback on eBay because they did the auction transaction well.
That said, they do seem to have some risk factors based on their ebay usage:
(1) they have few feedbacks and many of them are suspiciously identical and vague
(2) they use the private bidding method
(3) they have only been an eBay seller for a little while
(4) they are in the Knoxville metro area, which is unfortunately known for a mushroom-like profusion of scam timeshare sellers. they may or may not be one of these.
(5) based on internet evidence they seem to be one of these "travel club" companies that is at best harassing and at worst a scam for SELLING your timeshare. BUYING a timeshare from an organization that does this may or may not bother you.
Bottom line: Be careful, know what you are getting into, and act accordingly.