I can't give you wholly objective opinion but I have owned a Mk1 MX-5 and my sister owns a VVC F.Choice will be TF160 or MX5 1.8 Sport
My sister has had a lot more trouble with her F than I had with my 5 over the same duration and mileage. Also, don't be worried about the 5 being front engined - Mazda have applied a lot of effort to get the polar moment of inertia very low, so it handles superbly.
However, I would say that the interior of the F is significantly superior to the 5. I suspect that the TF160 will be quicker - having more power - and will pull more g in the corner - the 5 is quite softly sprung - but the 5 is still a hoot to drive on the twisties.
If you are into tweeking your cars, guys in the States have blown their MX-5s (well, Miatas) to ~350bhp and there are plenty of suspension mods available as well.
In a nutshell, they are fairly different cars but both will put a smile on your face with the top down. Go and drive them both a couple of times and then buy the one that suits you.