Hatsan TactAir Volt.........?

I would personally buy it from Wal-Mart only if that option becomes available and specifically buy their 3-4 year warranty protection plan. 

Wouldn't want to be another victim of unreliable cheap (non Yong Heng) compressors.

I would also wait AT LEAST ONE YEAR OR LONGER to see how many "another paperweight due to many failures after one year warranty is over" - to "not a single issue nothing wrong at all with mine after a years worth every day use" user ratio.

It's YOUR MONEY to gamble AND it's ONLY $500.00!!!

Looks like that can at least keep a lot of papers from blowing away so it still is useable even when it's broken.
 
I really think a Chinese hand pump with a good filter would be more reliable than a sub $600 non Yong Heng with 4 year Wal-Mart extended warranty based on longevity feedback (or the lack thereof based on brand new offerings).

There's the Altaros booster that's around a little more than the budget but you still need a really good high cfm compressor with a good sized built in or external reserve tank to feed it.
 
There has already been problems. 

You feel free to gamble. I would personally only use it to fill up to 3000psi max if I were forced to use it and depend on it being reliable. Thats just ME though. I would wait 10 more months though before making a decision to buy something like an unproven high pressure compressor that's too new and really unknown even if I could afford to throw it in the trash when broken.