I have used the tube store as well, but I live in the US and it is in Canada. Not that there has ever been a problem, but the Tube Depot got it to me quicker due to the fact it didn't have to go across a border. Both places are easy to deal with and have a good selection of interesting tubes. I tend to get my mic tubes from the Tube Store because they had a better stock of JAN tubes. A little ironic, but oh well, they had the goods.
Patrick