We also loved Casa Paolpó; we stayed there back in 2010. Super charming with warm and friendly service. Fantastic view of the lake and surrounding volcanoes from the spacious rooms. Food is terrific - I'm not surprised that it recently became R&S.

Not sure how it measures up nowadays, but we enjoyed Hotel Posada del Angel. Very intimate property (about 6 rooms, IIRC), and the Room: Rose Suite (#5) on the 2nd Floor gave you a roof terrace all to yourself. Room service breakfast on the terrace with views of the volcanoes was one of the highlights during our time in Guatemala. For what it's worth, it was the exact same room that Bill Clinton stayed in during his visit to Antigua a while back.