I bought a Megane Scenic from them a few months ago.
Saved a load of money compared to a dealership and i picked the car up the following day so no waiting around.The service the offered beat any dealership i have used in the past.It was a good experience all round
As the car was brand new but pre registered i took over the remainder of the warranty which in my case was 2 years and 3 months as well as an extra year i took out to kick in when the Renault one ends so i have 3 years and 3 months warranty on mine.
The downsides are that im not the first name on the V5 and it is missing a few bits like window etching and locking wheel nuts.( Small price to pay)
The upsides in my case were saving about 5k for a like for like car from a dealer.I asked a dealer how much for the same car with the extras mine had on and thats how much i saved.No doubt i could of done a bit of haggling but i doubt they could of got anywhere near what i paid.
I sorted my own finance out before i went and went armed with the best internet deal i could find...they even beat that because they have their own financing department on site who beat my best on the spot.
I wouldnt hesitate to use them again,infact they were so good and i saved so much i doubt id use a dealer ever again to buy.
I didnt even ask about part ex prices beacuse id imagine they would be crap because of the savings you make buying so i sold my part ex myself.
Well worth using IMO
Hope this helps,if you need to know anything else fire away