The twin versus single debate is as old as flying and I'll avoid it here for the benefit of our collective sanity. Suffice to say is that one thing is for certain; owning and operating a twin in Europe with the horrendous Avgas prices here is not for the faint of heart. There is however one exception:
The Tecnam P2006T has two Rotaxes and burns less than 10gph (8.8gph economy cruise) in total, Mogas or Avgas, still delivering twin engine safety. And as you know, Rotaxes are cheap to overhaul and have become very reliable. Granted, this is a new aircraft, so you have to shell out some mullah to get it which will offset some savings. About $420K new or $300K used. That said, I just did the calculations for 100-150hrs usage per year, and the Tecnam ends up being cheaper to operate per hour than my old twin.