Guatemala was one of the pleasant surprises of the trip. Before visiting it i didn't know a lot about the country, but there we definitely some great little towns and plenty of things to do, not to mention the fact that travel there is pretty cheap.
Xela was a great little town and so was Antigua, but I suggest you spend as little time as possible in Guatemala city, its probably the most dangerous city that we encountered on the whole trip.
If you do visit Xela (Quetzaltenango) make sure you have breakfast at the Black Cat Hostel near the town square, the guacamole omelets are unreal. It is definitely a great place to stay, if you need directions it is listed in most of the latest guide books.
Definitely check out Antigua, it’s a really cool town with lots of old colonial buildings, bars and some great restaurants. A lot of people from Guatemala City go there for the weekends so it can be quiet busy but it still has a great vibe.
Also make sure you take a tour to the Pacaya Volcano its well worth it, Being able to get so close to the lava made for a pretty unique experience being able to get so close to the lava made for a pretty unique experience.and for us one of the highlights of the trip.