Planet X 52mm Carbon clincher

Hi there

Does anybody have any experience with these wheels?

http://www.planetx.co.uk/i/q/WPPX52CCL/planet-x-52mm-carbon-clincher-whe...

I'm looking at getting the Planet X RT58 Alloy v2 as a winter/ride to work bike on the cycle to work scheme. With Planet X bike builder I can upgrade the wheels and still come within the £1,000 voucher limit. Plan is to swap the wheels which are currently on my Supersix Evo for the Planet X ones. 

What I really want to know is will they be an improvement. The wheels on the Supersix are Superstar Components Elite 24s which are great, had no bother at all with them and they weigh 1492g which is 300g lighter than the Planet X. Is 300g really going to make a huge difference? Also I live in north Essex and ride Essex/Suffolk/Cambridgeshire mainly so the odd drag or punchy hill but nothing major in the way of climbing. 

I'm guessing at speed the Planet X wheels will be faster and also a tad more aero. Plus they'll look awesome on the Supersix which is the most important thing obviously...