I was given one for free as a buddy ordered it on accident, it is the 300w model

It is currently powering my Am486 DX-100 build. Seems to work just fine, it seems fairly cheap however and is super lightweight.

I wouldn't try to to use one for anything heavy duty but for what it is, it seems just fine too me. YMMV

I bought one of the 300 watt ones from newegg a while back (they no longer have them in stock), and it seems to work ok from the little I used it.
I just used it to test some motherboards, and I may use it in a 486 machine I have.
The date on the warranty sticker that they use to cover one of the screws says 5/2017, so if that is true, they are new.
However, the unit is very light which some here say is a sign of poor quality, and I had issues with wires that were not crimped properly pulling out of the molex connectors.
Otherwise the fan is quiet, and it seemed to put out proper voltages.

I saw this review a while ago that pointed out various physical QA issues with one of their 400w TFX units. That was only one sample, which did pass all of his tests anyway, but it made me wonder a little. I can't imagine that niche AT units would be nearly as high-priority of a product line for this company compared to their models aimed at modern ATX-based systems, such as that TFX unit.

Thats a lot of watts for AT isnt it? I have several of those new Startechs and think they're great.

I purchased a new 250W AT PSU at Microcenter back in 2012, the fan gave out, and the PSU blew white smoke the same day. Here's a suggestion: use a new ATX PSU and purchase an ATX-AT w/ -5VDC and Dummy Load (3.3V) for your older systems that you paid good money for. I have a 145W PSU in my Packard Bell that's original and it still works. However, my plan is to put a bigger wattage PSU in there (preferably a 230W ATX PSU with the adapter).

Their wattage claims don't give me a good feeling. Athena Power are known to push junk power supplies, similar to Apevia. At their best, they can be as good as FSP. At their worst, they're fire hazards and shouldn't be stored indoors. Unfortunately, lying about rated power goes hand in hand with fires and explosions.

You can do better. As Badmojo said, while not as nice as, say, Zippy or Flextronics built supplies, Startech PSUs are known to be decently constructed at a reasonable cost, plus they're available in AT and ATXv1.3 configurations which is great for older hardware.