The reason the Yaesu is $250 is that it's (1) made in Japan, (b) well made in Japan, (3) a well made in Japan linear supply and (d) well made in Japan linear supply /by the people who designed it./
That said, it really is a very highly priced supply compared to the market and there's no reason you need to spend that much on a supply. It's by no means a bad supply, but about 50% or more overpriced.
Now the QJE, that's is a Chinese copy of the Alinco DM-330MVT, which if you're gonna steal someone's design is one very good switching supply. The Alinco is a VERY highly regarded supply.
But QJE can charge less because they didn't have to spend the time engineering it and don't have a decade of debugging and customer support behind it. They are new to the market, so I dunno anything about them. Caveat emptor, you might get want you pay for. Or maybe not, could be a great deal like the Wouxun HTs.
None-the-less, both are overkill for a 2m, 50W mobile. You only need about 10~15A of continuous current to run your radio. It's not bad to have more and you never want less current than your radio needs.
Personally, for a 2m FM mobile I would run a Astron SS or RS model, in both lines a suitable unit would run about $100 or so. Astron makes solid supplies in L.A., CA. I run my station from a RS-35M and can personally vouch that it is very low ripple and reliable (I measure about 3mV at 20 amps set dead nuts on at 13.8V). The thing is built like a tank, weighs about 20 lbs.
But I'd probably be looking at the Astron SS-18 for a dedicated 2m FM supply. Much smaller and weighs 4 lbs, but can do 15A continuous and 18A transient.