Hi
I have a lot of experience on the Seneca Five twins! It really comes down to what your buyers mission profile is?
We compared a Seneca Five twin to a Piper Malibu the piston variety of the Meridian and the Seneca won all round surprisingly beating the Malibu climbing to 20 K
This owners needs was to fly every week across the Irish Sea, day, night, summer, winter and it comes down to the old argument of single versus twin
Ok the Meridian is a turbine and hence more reliable but a twin is still a twin and the owner wanted that comfort factor!
I flew it for him for a year and it was without doubt the right choice a comfortable economical twin which handled all weather thrown at it
Also remember the costs of running a turbine
Really the prospective owner needs to work out his mission profile and fit the aircraft to that.
I flew the Meridian and TBM750 850 and frankly felt the Meridian felt like a toy in comparison. But then again I don't have a lot of experience in the turbine singles and that is more an impression