Just over 4k into ownership of mine now (non-cupped non cup with no options except parking sensors), and in no particular order my thoughts are;
MPG - manageable, accept it punches a bigger whole in the air, costs more fuel to get moving due to mass, and tweak your driving style accordingly, and you'll not suffer too much. Give it bootfulls everywher and you'll suffer lots.
Handling - On a par with the MkIIs, no better, no worse. Just as chuckable, just as adjustable. Seems like they're not as good as the earlier ones due to the increased grip, so to get the same experience, you need to up your pace/commitment.
Interior - positively light years ahead of the MKIIs, doesn't feel much smaller than my Focus, takes two kids in the back in seats/on boosters with ease, fit/finish and materials/textures make it a nice place to be. Gimmicky though it is, the gearshift/limiter warning beep is useful. Very useful.
Driving position - hello gear lever (no stretching), good standard chairs, reach adjustment on the steering wheel is a beautiful thing.
Gearbox - nice mechanical feel, doesn't like being rushed, very positive engagement. Short throw is nice.
Engine - feels really quite grunty low down despite the car's weight. I routinely overtake in 6th now I've learned where it works best. Seems to me like a lot of attention's been paid to tuning the noise of the car - below 2k it makes barely a sound, around 2.5k the intake and exhaust start growling a little, at 4k it makes proper noise, and from 5k upwards it's quite raucous, it encourages you to rev it hard. I'm now running 99 RON through it and it really seems to have strengthened the engine low down...has improved MPG a little too to offset the increased cost.
Brakes - stupendous, astounding, breathtaking, terrific, remarkable. Cost of OEM pads and discs from G172 on here is comparable or cheaper than OEM MKII replacements. Yet they perform the way they do. I really truly actually love them.
Pedal feel - good. May fit lines, may not, a few more trackdays will tell. Brake pedal was consistent throughout the day I did at Goodwood but I was going pretty easy on them.
Throttle response - woolly, very woolly at low revs. Seems to respond far better higher up. Am considering a Sprint Booster as a fix. This is genuinely the only negative I have about the whole car.
Suspension (Cup v non Cup) - only ever passengered briefly in a Cup which is/was good for me because when I first drove mine I wasn't expecting anything other than a good handling hatch. I can honestly say that there's not one single circumstance where Cup would win the day outright for me. On track it would be sharper definitely, keener maybe, but then for the next ?,??? miles before the next trackday it's got to trudge up and down the lanes and B-roads of West Sussex rattling the car and me to bits. As someone above said, the non-Cup on a lot of day to day surfaces will definitely have the edge/pace over the Cup as its grip is very very exploitable.
Back to back Cup v non-Cup review by Evo magazine here (this was a huge factor in my buying decision)...
http://www.evo.co.uk/carreviews/evolongtermtests/256042/renaultsport_clio_200_cup.html
So to sum up, get one.
Don't worry about the options unless bling floats your boat, really, none of it is needed. If you can be free on the suspension/chair/options front, the secondhand market is your friend as no one wants soft suspension (for girls only apparently) or standard chairs (wot, no recaros?), so when they come up, ridiculous deals can be done.