Is there a better DAC than the Schiit Bifrost for $300?

I have a Schiit Modi 2 Uber as my DAC. I'm not completely dissatisfied with it but understand that it is low end and that there must be room for improvement. I've got a nice older system but I'm not a fanatic about SQ (yet). I could use the Modi elsewhere or sell it...although Schiit just came out with the Modi 3 so the Modi 2 Uber is only worth about $60-$70 now.

There are open box Bifrosts on eBay for around $330. They are $400 new.

My questions are:

Should I see noticeable improvement going from the Modi 2 to the Bifrost?
What if I just went to a Modi 2 Multibit at $250 new, $200 used?
Is there another DAC I should consider in the $250-$300 range?
One would assume as long as you have the correct plug end and the power supply is of correct voltage and sufficient amp rating then I would say any brand of tablet charger would work.
But walwarts are not usually the best source for power for any dac imho.

I got big improvement in sq on a mytek Brooklyn by going from a mains 115v cord to a quality iFi power supply ($50) rated exactly to match the Brooklyn.

Sometimes you do still get what you pay for.
Yes that ifi power supply looks like something I would be more comfortable keeping plugged in all the time to a dac instead of tablet charger. 
another good budget audio company is IFI Audio. They have a few DAC's and they aso get great reviews. I've owned one of their IFI Iphono2 phono stages that at $500 was punching well above its price point. Highly recommend IFI products.
@OP, check out HifiShark.
They have a pretty complete listing of equipment around the world- which you can filter accordingly. Ebay is just a small part of the 2nd hand world.

Musical Fidelity, V90-DAC

$299 on Amazon, and 30 day hassle-free return if it doesn't sound better than your Schiit.