I have only ever filled up with shell V-Power (I'm a strong believer in quality fuel).
I do agree with the "quality fuel" bit but the higher RON (V-Power is 99 RON) is simply not needed with these engines. In fact, to burn it properly will require the EMU to self-adjust and if it can't do it correctly, you could end up with worse fuel consumption rather than better, or worse your exhaust could even contain un-burned fuel, thus damaging your cat.
Shell state that V-Power is safe to use in ALL cars that are designed to run on leaded and unleaded fuel. From Shell website:
Q: Is Shell V-Power high performance fuel suitable for all cars?
A: All leaded and unleaded vehicles can benefit from using Shell V-Power. Some older vehicles may need to use a valve seat lubricant with Shell V-Power to help protect the valve seats recession. If in any doubt, it’s best to consult your manufacturer’s manual or your local dealer.
I realise that I'm not going to get a massive performance boost from using V-Power, but I like the fact that there are cleaning agents in the fuel which keep the engine nice and clean. It only works out at a couple of extra £ per fill up, I think it's worth it for that kind of money. I've put nearly 7000 miles worth of V-Power through my M2 and it runs just as sweet as it did when I first picked it up.
However, I will give some 95 RON fuel a go over the next few fill ups and see if there is any difference in ecomony/performance. If I get better economy then I'll start filling up with the 95 RON stuff.

Update: Also checked the M2 Manual and it states that the engine runs best on ron 95 and above. Looks like it can take advantage of higher ron rated fuel.