We stayed here for a week in early May and loved every minute of it! The apartment is warm and inviting, fully kitted out with modern furnishings and all the kitchen you could possibly ask for. It's in a great location for seeing most of what San Francisco has to offer. The keyless entry system is great, no need to worry about keys getting lost etc.
The Marina district is quiet, peaceful and a stone's throw from the Bridge. We'd originally planned staying in the Castro area but glad we chose here, it's far easier to walk and see things without relying on public transport.
We didn't get a chance to meet the owners, but the property manager Pavla was very pleasant to deal with.
In short, if you're looking for a great launch pad to see San Francisco, look no further.