Hi Andy, I'm a lucky boy in that I have both a M3W and a M4W. Chalk n cheese.
I think that unless you are an ex biker or something you will find the three wheeler far less usable. SWMBO is not too keen on it either. I think it's fab but def a fair weather car for me, a Sunday afternoon toy. Why don't you hire one for a weekend?
Most pre 2014 will have been upgraded by now but I think long term ownership costs and depreciation will be considerably greater than your 4/4. Keep us informed!