Sewing Machines Direct get a big thumbs up for me - I like to do a lot of free motion embroidery, and am very heavy on the thread - I have used Simthread before, and was quite happy with its performance and price. I saw SMD were selling it, so I ordered 7 various reels online yesterday afternoon, and couldn't believe they arrived in the post the morning!
I might just have to order some more.........(£1.39 for 1000m reels) whereas 1000m of 'Glide' thread is £4 per reel! Have used both and not much to choose between them (apart from price!!)