Ran into this post and had to comment, been running 35 D3's since early november
So far trying better than a 7 various pools, with some conviction i can state atleast for a straight DASH payout, Zpool is 20% more.
I'm not biased and i run rigs everywhere except nicehash, but for DASH Zpool is the only place we are pointing in the immediate term.
Frankly it gets tiring bouncing pools every 15 days, but the payouts don't lie for DASH.
There's always going to be various other instances especially for Alt coins, i can't comment on those only on my first hand knowledge.

The word " Scam " shouldn't be used lightly guys, in a space where unfortunatley we are rampid with far too many true ones.