Given that some people like the idea of a limited company owning the plane to limit liability (though the value of this is questionable in my mind, since the directors could still be pursued) I guess there is a small danger of the plane "bringing down" your company. Anyway, in my case the plane could be owned by an offshoot of my main company if this mattered.
The other question mark in my mind is still over taxation. I guess I need to talk to an account who has specific experience of this kind of thing (mine doesn't). For example, if one could get the inland revenue to agree to only tax you on the benefit you actually receive (rather than the idea is always available to you and you could therefore fly it X,000 hours each year) then it shouldn't make any difference if you pay for it or not - after all you have to pay tax on the money that you use to pay for the rental, which would be the same as the tax you'd pay on the benefit. If you see what I mean...
Also, presumably one could legitimately fly X hours per year for free, because one needs to "check the plane", "check potentital renters", etc. as an operative of the company that owns the plane. Perhaps for other reasons too?