I’ll contribute my experience with DB Electrical: My alternator was no good when I bought my 400-hour M4700. (It only put out 11 volts.)
Shocked at Kubota’s price for it, I bought one from DB via Amazon for $70. It was a simple bolt-on and works great.... impossible to distinguish from the OEM. (Remember, the Chinese are famous for copy-catting and this is no exception.). Two years later ...still working perfectly.
The local automotive starter/alternator shop wanted $180 to repair my failed alt, but online via Ebay I found the internal regulator for $18. It was a simple disassembly / re-assembly and took it in to AutoZone for their free test... works great! Now I have a spare.... if only that cheap chinese copy would fail...
A month or so ago you’ll recall I was having starter problems. I jumped-the-gun and ordered a $89 starter from DB via Amazon again. (Unlike Flip, I don’t care if Bezos makes a buck selling low-cost and shipping free to me... especially when it’s to my benefit.... I believe in free-enterprise.)
Turned out not to be the starter, and I discovered the dirty relay only an hour after ordering the DB starter. I cancelled the order thru Amazon, but it shipped anyway and after it arrived I tried to return it.... but DB wanted me to pay the $9 return freight. I complained to Amazon who agreed that records show I cancelled before shipment, and Amazon contacted DB, and a few days later DB emailed me a free-return shipping label. Maybe Jeff called them personally, I don’t know, but Amazon did right by me, and I’m not going to avoid doing business with a company that does what they promise as long as they stay on the right side of the law.
So... DB sells good stuff as far as I know and Amazon can be a good way to buy the stuff, IMO. I’ve also bought DB via Ebay, but I’ll bet Ebay would not have made DB pay the return-freight for shipping a cancelled order.