I have, I've bought 20 books from them in the last few weeks and no problems, I was a bit hesitant to use them at first due to unfavorable reviews online but I thought I would give them a go and it's worked out so far
Be aware that even if you order like ten books they will all ship separately, one of book depository's funny quirks lol.
Also if you shop from http://www.bookdepository.co.uk/givemefive and follow the instructions you get 5% off, remember that takes you to the UK site so be sure to check the prices between the two sites first.