Have Dinan Stage II and happy with it. However, as I never had ESS, I can't really compare.
I got Dinan stage II when I had full Dinan setup. Then I went back to Stage I tune after I took full Dinan off.
And I recently flashed Stage II again after installing Akra Evo.
Good thing is: My local shop called Dinan and got a confirmation of my Stage II tune ownership. So they re-installed Stage II at 1/2 hour labor only.
PAST: 14 F10 M5 | 11 E70 X5M | 08 E90 M3 | 08 E92 335i | 03.5 E46 M3 | 99 E36 M3