I have it. Britax Renaissance got 3/5 for ease of use and 4/5 for crash rating so did Graco Cosmic, Mothercare MX Sport got 2/5 for ease of use and 5/5 for crash rating. I think this info is about 1.5 yrs old.
I had already bought a maxi-cosi proiri when the report came out for ds1 and I have to say it is fantastic for moving from car to car and reclining but it only had a 3/5 for both categories, I would definitely have given it 5/5 for ease of use. Bought my ds2 a Britax Eclipse (from birth - 4), the shoulder straps always twist don't pull as tightly as the maxi-cosi and is a nightmare to try and recline once you have started to drive even with 2 hands. Also have never got used to moving it from car to car.
Don't know if this is any use - The AA website (theaa.com) had ratings for car seats from the motoring trust. Mamas & Paps Pro-Tec and Romer (Britax) Duo Plus came out top for 1-4 years. Don't know how current that is. Does anyone know where I can find info on which seats fit which cars? I know that Britax have this info on their website but can't find anything from other manufacturers.