I am on my first tankful of 98RON V-Power petrol I filled up myself after the initial 95RON tankful, which came with the car. Now I know the fuel gauge is not a truly accurate guide, but at 3/4 full, I had covered 270kms. I was VERY impressed. I am at 370kms and still well above half a tankful.
This has been only inner SE Melbourne Metro driving. Not even a trip on the M1. I get that on Tuesday!! Just local tram & non tram streets with heavy morning/afternoon traffic and lots of traffic lights.
I generally use Comfort mode to start off with and if I see a good run, I will switch to EcoPro mode to glide along. It really offers very low (engine & chassis) braking resistance. For those of you not familiar with Melbourne's geography, it is mostly flat. In heavy, slow moving peak traffic, On occasion, I cannot see any reason to shift out of EcoPro mode, even when moving off from the lights as the traffic doesn't move fast enough anyway and EP keeps up.
I have ASS active at all times and enjoy it. It certainly helps, no question.
All this with just 1,500kms on the 'clock'.
My E90 used to cover a little over 400kms a tankful of 98RON V-Power along the same routes. Same sized 60 (or so) litre tanks.
328i M-Sport, Estoril Blue, Carbon XP 35 Tint, front heated seats, black Dakota, Sports Suspension, Anthracite Headliner, HUD, Pro Nav, Sunroof, hk 600w, Bi-Xenon, 19" 403M wheels, Reversing Camera, DAB+, Xenon, BT Ext Connect. JB4 on Map 2 with Catless DP produces awesome performance in Sport.