I purchased a new Renault Scenic in 2002 and have had my vehicle serviced by the dealer ever since, even though it would have been much easier to have it serviced locally by a non-Renault mechanic. Renault advised me against this as they say that their mechanics/ technicians are sent to France or Singapore for specialist training in Renault vehicles and even though I might get the work done at less cost it would be unwise to do so. My daughter has recently purchased a used one-owner 2008 Renault Laguna hatch and it is almost impossible for her to take the car to the Renault dealer for servicing. Are we being over cautious in not using a reputable local service provider?
It really comes down to what you are comfortable with. Renault does send its mechanics and technicians overseas for factory training so they should be armed with knowledge to fix whatever problems owners have, but you do pay a price for that. My advice would be to use the dealer while the new car warranty is current, but then switch to a reputable mechanic after that, one that preferably has knowledge of Renaults.