I personally would go for the Tannoy speakers as they have a bigger frequency response and I rather like the sound of Tannoys. However I agree that the choice of speakers is a very personal thing and you should listen to them both.
If you really can't get to the store, then find somewhere that will accept them back as long as all the packaging is intact. You wouldn't choose wallpaper over the phone and you can't choose speakers over the web, but needs must!
Study the pictures and finish carefully, and measure exactly where they are going - most people get the size wrong in their head!