Claghorn wrote:My impression is that the smoother flatter surface works better.
+1 - I tried sanded glass, and it didn't make any difference. Not worth the effort!
Hairspray on smooth glass has me working pretty happily (always with a brim). I put down a fresh dusting before every couple of prints, which keeps it tacky. Inter-layer adhesion is now a larger problem than bed adhesion, at least. 
WRT thickness, thin = crack easily, thick = slow to heat and top surface temp lower than bottom (glass is actually a fair thermal insulator...). 3mm works well for most people as a balance.
SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi