My wife pushed me to getting a S5 Cab vs the S5 I was looking at when i picked it up a few years back and TBH I love it, My petrolhead mates are all talking about how its .2 seconds slower to 60 or whatever but on a nice day its soooo much more fun.
Its not the most lively drive but for planted sensible performance car it ticks all the boxes.
We're also thinking of getting an S5 cab to replace our sportback A5. I personally think they look great and confident we would also manage to cope with the tiny performance drop. I've yet to test drive one but encouraging to hear it's fun with the roof down.