Few variables to consider though other than how the car drives.
Yes the 182 will be slightly higher on tax/insurance but fuel economy on them isn't hugely different than a 133. Also if you have outstanding finance or more money tied up in a 133 (with them being most expensive at the moment) then a 182 may actually work out to be cheaper.
In terms of driving, the 182 is quicker in a straight line and I'd say in most road conditions, the handling is on a par with a 133 with Cup chassis. The difference though is that the 133 feels less fidgety and gives you more confidence in the corners. The 182 is by no means a poor handling car.
The looks are subjective, yes the 133 looks modern and more fresh but the Clio isn't a bad looking car. The exterior bits and pieces on an RS Clio make it a subtle but beefier looking version. I do prefer the looks of the 133 side by side with 182 but I wouldn't be embarassed being in one, if anything they've still got that little something that makes them specisl.
Interior wise, the 133 feels more modern. I'd say the interior on the 182 feels the most dated aspect of the car. That said though, as standard a 182 will out do the Twingo in terms of interior features. Only the Gordini can come close to the toys in a Clio 182 as standard.
That's my thoughts on the subject anyway so I hope that helps. I've owned a Clio 172 'full fat' and driven a Clio 182 Cup very regularly a few years back, now I've got the Gordini 133 non-Cup and the Mrs has a 133 'full fat' with the Cup chassis. Fair bit of driving of both so hopefully a decent comparison for you.