Being from the U.S.A. you should find it 20% cheaper than we poor British folks as you will be able to claim the Value Added Tax back.
Driven grouse are very, very fast and come in low so there are safety considerations. Some sort of instruction is a must for someone who has never shot this type of game before. Beaters and Pickers-up are hard come by and can be quite nervous creatures if they notice inexperienced Shots in the line up. I've seen grouse go past un-shot at simply because they were not even seen!
Most English moors are reporting good numbers this season. I have not heard reports from north of the border as yet.
Not necessarily giving them a plug but I work for this Landowner on one of his English Estates. This is his Scottish Estate;
http://www.glenmuick.com/activities.aspx and both walked up and driven grouse shooting can be arranged (plus accommodation) together with Roe Deer and Red Deer stalking and salmon fishing plus other types of game shooting. Nice part of the world and not too far from Aberdeen Airport. The Estate is next door to the Queen's place at Balmoral so the neighbours check out o.k. Lagopus.....