Does anyone know a more reliable provider?
It just baffles me that manual/third-party bid-sniping is still a thing. eBay has had automatic bidding for more than twenty years. You'll pay the same whether you put in the winning bid a week in advance or 5 seconds. But people see that "you lost this auction" notice and they're irrationally convinced that it would have gone differently if they'd bid at the last minute, somehow.
Also this helps when placing bids on auctions that end when you're asleep and you want to effect the above. I've tried to do it manually in the past but naturally life intervenes and you're somewhere with no signal or in the middle of something. Having tried it both ways sniping is definitely better than regular bidding.
Sniping approximates sealed bids, with the highest-bidder the second-highest sealed bid amount or a small increment above it. (Unfortunately for eBay, that would tend to decrease their cuts, unless the appeal of the sealed bid format brings in sufficiently more bidder activity.)
Another advantage of the software/service is that it automates. If you want to buy a Foo, you can look at the search lists, find a few Foos (possibly of varying value in the details), say how much you'll pay for each one, and let the software attempt to buy each one by its auction end until it's bought one, then it stops. If eBay implemented this itself, it might be too much headache in customer support, but third-parties could provide it to power users.
(I don't buy enough on eBay anymore to bother with anything other than conventional manual bids, but I see the appeal of automation.)