I hear the P2006 has a few limitations.
It can carry fuel or POB but not both, basically instructor and student with a reasonable fuel load or 4 POB without a lot of fuel.
According to Tecnam's brochure, the aircraft has an MTOW of 1180 kg, a standard empty weight of 780 kg and holds 200 litres (= 144 kg) of fuel. This results in a useful load of 256 kg, which should accommodate a very substantial instructor with an equally substantial student. This with full tanks, which equals almost 5 hours endurance (20 litres/hour/engine).
Are Tecnam's specifications in the brochure really that much off the mark?
I fly from an airfield with a 400 m paved runway and the FBO I use there has a P2006. It operates in and out of this short runway without problems. Which other run-of-the-mill twin can do that?
I hear that there have been some mechanical glitches with the aircraft, but absolutely nobody at the FBO is critizing its flying qualities. Quite the contrary actually, it's supposed to be very forgiving and simple to fly.
Moreover, with AVGAS costing around € 2,50 per litre in Germany, being MOGAS-capable is a HUGE selling point here. I've never given any thought to a multi-engine rating before, but with the arrival of this aircraft I certainly am. Going for a Seneca (the standard twin trainer available around here) would ruin me - and probably kill me as well.
Putting Lycomings/Continentals on it would spoil the concept. It would be more expensive to purchase and operate (no MOGAS). If the frontal area of those engines is larger than that of the Rotax, and the weight larger, then performance would be affected too.
I have quite a number of hours in another Tecnam product, the Tecnam P92E. I like the build quality - and I like Rotax 912's too!