G-ICBM is a Uk turbine Glasair. On a CAA permit If I recal correctly
See
YouTube - Glasair Turbine G-ICBM
I believe it is comparable in cost to a piston engine to run. It is faster, lower fuel cost and the TBO for the turbine is higher.
This one did have a nosegear failure which required a new prop and turbine stripdown, which I expect changed the cost equation significantly.
ZA