We were extremely happy with Tjakko's place(s). He has two rooms and we stayed in both -- one at the front of the building (can be noisy from the bar and street below) and a larger, even better one (with full bath) at the rear of the building. The latter is quiet, has a superb view over neighborhood gardens. Both have king size beds (a rarity in Amsterdam), with a firmer mattress in the rear room.
Amenities are first class throughout -- with much attention to detail: Nespressso machine with pods, milk, beer and water in the fridge, fresh flowers, cookies, etc. Tjakko's welcome was most warm and friendly, he was a mine of information and extremely responsive. He even offered to take us on his boat but, sadly, the weather didn't cooperate.
The location couldn't have been better. There's a great bistro- bar in the building, a top-class organic supermarket (Maarkt) at the end of the block, a supermarket 2 blocks away and within easy walking distance to many of the major sites. There's also fabulous boutique shopping and excellent restaurants within a few blocks.
We couldn't recommend Tjakko and his properties more highly and look forward very much to returning (in better weather).