Hi,
I'd also like to recommend an additional letting agency - Albany Lettings - they've worked with us while we're still here in the US - they're brilliant, friendly and very helpful. I've know a couple of folks who've been able to work with them while still here in the US (meaning they're able to secure flats for you and do all the paperwork for you, if necessary, while you're still here in the US).
Although we've made the decision to go to Glasgow instead of Edinburgh (more family closer to Glasgow rather than be with the 2 cousins in Edinburgh) - I've sorely missed being able to work with Albany (since they don't have an office in Glasgow)