We love love loved the location of the apartment.
You are 5 mins walk from at least 3 major subway lines to get you to lower/mid/upper Manhattan or Williamsberg with no delays. The area of Boerum Hill has plenty to keep you entertained (we ended up spending about 5 days in total not leaving Brooklyn).
We spent 3 weeks at Marks place and were very happy.
The studio Apt was clean and is well arranged. Plenty of space for multiple bags, closet & cooking facilities.
I highly recommend staying here. This was our third trip to NYC and first time staying out of Manhattan.
This was so much more affordable than Manhattan and you don't miss out on anything, just gain knowing a great part of Brooklyn well.
Your local store for groceries is Brooklyn Fare as featured on Anthony Bourdain's No Reservations Brooklyn Episode. And if you get the opportunity the Chefs Table is 5 mins walk away.
My only comment would be that you can hear upstairs noise on occasions due to the age of the brownstone and this is clearly outlined in the apartment listing.
Mark and his family are very receptive to requests to lower the noise and we only had to do this once (Sat night, Halloween & I had the NYC Marathon the next day-bad combo!).
I never met Mark personally but had great email & text communication with him, and his son even popped down to help us with the tv settings, lovely family.
I wouldn't hesitate to stay here again!