Our stay in Benjamin's apartment was simply superb. The place is as amazing as it seems on the website. The location is perfect, with several Metro and bus lines within a minimal walking distance, Place de Vosges just 200m away and all the Marais' attractions within a short walking distance. Everything else is at hand due to the great transportation system.
Benjamin himself was very helpful in our communication via mail (unfortunately we haven't met face to face) and his recommendations for the area were great. The concierge who met us was also lovely.
Don't miss the bakery on the corner. You'll get there the best supplies for a Parisian breakfast or afternoon picnic :-)

The only point for improvement is the water pressure in the shower which is very weak.