Best bang for buck integrated amp for $500

Former owner of many compact amps. Here is my compact amp ranking.

1. Burson Funk with Vivid OP amp upgrade - Great bass, warmth, and clarity. This amp is a unicorn.
2. Rega Brio R - Exciting forward sound, unrefined treble, high noise floor, good tone...enjoyable. 
3. Emotiva Bass X 100 - Great build and power for the money. Average across the board for sound...pretty neutral sounding. Brio R has better tone and is just more engaging.   
4. Audioengine N22 - Good mids and pleasant treble. weak bass. warmer timbre. sound lacks dimension, body, and bite.
5. Parasound Zamp V.3 - Tonally cool. Felt like much less than 45 watts. Bad harmonics. 
6. Ice Power 125ASX2 - Sounded like bad Class D. Great bass and bass grip. Mids and treble were very unnatural. thin, cool, dry sounding amp. Would be good for home theatre. 

could it be the wistling tea kettles themselves?

I took a look at the Burson Funk and if one needed an amp for primarily headphones but wanted speaker capability it could be a good option. 45/35 watts at 4/8 ohms respectively, while my amp is about 60/35 watts for speakers but hasn’t the output for headsets as the Burson. It does add preouts and a MM input, as well as a basic USB, plus two RCA inputs for less.

The Burson took a price hike to 799? A review stated priced from $544, that’s quite a recent hike unless I’m missing something?

Why did you buy two okay amps instead of spending the total on one good amp? 

Because i have a only ok amp budget ?.  The Burson sounds interesting i may look into that amp.  

When your budget is limited you limit your choices for sure, maybe i need to save up more money and up my budget. 

Im not saying the Rega IO was bad at all, it was quite good, just lacking in low end in MY OPINION, everything else sounded very good.  I dont want to buy a sub, im in a very small room and dont really want to go the sub route.  Maybe bigger speakers front ported would have gave me more bass, im limited how far i can come off the wall on a desk.  I dont have a ideal or even close to ideal room and space to setup.

Im finding maybe i need a good headphone amp and call it a day, and when i move i will look for a larger more friendly audio room.  Trust me my box of room sucks for audio, well amp and speaker wise.