The Contitech kits, not to be confused with the cheap "Continental" kits, are more than up to the job and normally include the OE BRS idlers and Littens tensioner. There's only so many people that actually make belts to so I wouldn't worry about the quality here either.
I only use genuine Renault kits these days and agree, this is an area where you really shouldn't skimp on quality but have used the Conti's myself in the past and they've been great.