This is a nice apartment in a really good location, 10 min walk to St Marks Square (provided you don't get lost) and the Castello region is nice as it is close to the main area but also borders the Eastern end which is quieter, it is only a few minutes walk from the boat station and it's down a dead end alley so no noisy traffic (pedestrians) and the neighbours in the apartments were all quiet. It has good amenities, a very effective A/C as the roof top apartment can get warm (we closed shutters and left windows open on going out - to keep it cool). The host in Venice is very responsive and helpful.
A few things to note - it is a 3rd floor flat so a few stairs, by virtue of its height the water pressure is low (so to have a hot shower you need to run the hot tap in the bathroom whilst showering - then no problem - no shortage of water) and lastly the water pump in the attic is a bit noisy when it switches on, so if you are a very light sleeper then ear plugs (which are always a good thing to travel with if doing city trips). But a nice flat in a good area. A good fruit/veg. shop 100m away and a large supermarket within 5min.
What we enjoyed 'the most' - Church of San Giorgio Maggiore (a bell tower with a fantastic view of Venice, the attached monastery with a really good tour), The Architectural Biennale in the Arsenal (interesting stands and fantastic buildings, good cheap lunch) and two small artisan jewellers: Sara Senigaglia on Murano & Nicoletta Venerando's Studio (NV1A) on Burano - both unique and not expensive.