Hi there bimmerpjp, and welcome to the forums (and Renault ownership).
Mine is the diesel, so I can only comment on what will be common to both petrol & diesel engined examples.
Good points; space, comfort, value, equipment, rarity, unique design, they tend to be well-looked after, parts availability is good as they are still in LHD production, safety, good handling for such a large car.
Bad points; Renault dealers tend to have little/no experience in fault-finding, a few recalls - make sure all work has been carried out prior to delivery, depreciation (although if you buy at a good price and intend keeping it for a while, then its less of a problem), tyre consumption & price (shop around - I buy my tyres at £105 each), large windscreen prone to chipping (but I can fix my own
), cost of spares can be very high (keep your car under warranty), electrics can be a bit hit or miss - check it all works.
Don't be put off that one list is longer than the other - the plus points have more magnitude in importance.
I purposely avoided the petrol, because of the fuel consumption - my car is covering around 20k miles per year, but if you plan on a significantly lower mileage (or you have deep pockets), then its less of a factor.
All the best with the purchase.