Although the KZ offerings are great for their typically $10 price I found the E80's to easily outperform all of the KZ offerings I've tried so far.
They'll have a lot less midbass than the Pistons though but subbass extension is very good as well as the overall bass quality.
If you're in the US and can pick them up for $50 I'd say it's a no brainer. I paid $70 for my pair and still consider them excellent value .
You post this on the KZ thread... blasphemy!!!