We've stayed here now 2 1/2 times. 2 1/2 because when we were last there we changed our plans, left our luggage with them and headed off to Antigua for a few days. Was this a problem? Absolutely not. And that really sums up the hotel. Nothing is too much trouble and everyone from the owner down will go the extra mile to help their guests in whatever way they can. All the normal stuff like pickups (from wherever), transfers, onward bookings, etc up to offering to walk with you to find a delicatessen.
The rooms are clean and spacious and ours came with microwave and fridge. There's no restaurant (except for breakfast), but they have the menus of the local restaurants that offer delivery, there are supermarkets (and that deli!) within walking distance and the hotel will happily lend you everything else you need cutlery, wine glasses, corkscrew etc - so you're set.
I don't know if/when we'll visit Guatemala City again, but I do know that if we do we'll always stay at Dai Nonni!