Same here; I get that. My PSU is crap and thus, I have researched it extensively. Your best bet is the TX650 v2 at this price point.
Edit: I didn't even see that you had a HX520 atm. This is more than enough. Save the money and keep it unless you intend to crossfire in the future.
Leaning towards the 650TX v2 then. I know I could get by on less power (this 520 would probably be just fine) but a lot of the good quality power supply lines start at 600+ now and it's hard to even get a high quality 500w psu.
In any case $90 isn't that much to ask for a power supply so I don't mind paying it. I just wanted to make sure there wasn't something better in the same price range +/- $20.