I was Air Force, so no idea if our rain gear was comparable to the Army poncho. Ours didn’t strike me as anything special, but then again the one I was issued was several sizes too large, so I kinda hated that thing by default.
The best military surplus stores are going to be the ones near military bases - they have constant stream of new inventory coming in from folks who separate and want to make a quick buck pawning off their issued shit.
And while there are definitely a few gems among military inventory, don’t make the mistake of thinking military = high quality or even high durability. To the contrary, most of it’s the result of bidding wars for a government contract, resulting in the absolute cheapest shit available.
Idr the brand, but sticking with the boots example, the ones I was issued in basic training barely made it to the end of basic training. Those things were absolute trash.