I too am a company car driver, love the tax benefits, must say! In reply to your questions:-
1) One of the key musts I had on my list was an automatic gearbox. Whilst the CVT version in the CT is not a true automatic, I find it fine, whilst a little strange at the same time. Gets a little getting used to the way it revs so high, sounds like the engine is screaming at times. I dread to think what it must sound like to someone outside...........they must think you (or me) have lost the plot
2) I came from a IS220D to the CT so that was a drop from 170bhp. To be honest, I do not notice any difference at all, if anything, the CT is quite potent, especially when in sports mode. I have never had an instance in 12 months of ownership where I felt I was 'down on power'
3) Yes, space is at a premium in the rear and boot space is not the best. However, can fairly easily get 3 kids in the back (11 - 17) and it is not too bad for adults either, passenger / driver may need to adjust their seats forwards a tad but not too much
Overall, I am delighted I went to for the CT, whilst it may not be the most powerful / largest car it suits my needs, saves me £100s a year and I do generally love the car, have not had a single issue with it in nearly 12 months of ownership.