SPFs are great -
Weak spot of the SPF as far as I can tell are fairly petty.
1. Roll bar not quite at the right angles.
2. Radiator is mounted as such that it tilts forwards as opposed to tilting back.
3. (This ones debatable, but) shape of rear arches aren't quite the same (or as nice) as say an ERA, Kirkham or CSX.
Else, not much else I can recall.
With regard to your other questions.
They're all easily enough negotiated without drama.
The way I see it. you can't go wrong with an SPF.
FWIW: I don't own an SPF, nor do I have shares in the company.