The Lumia device range is superb......
Nokia are supporting the current range through 7.8 which delivers everything that can be through software; this includes additional camera functionality (from next month), Nokia Drive 3, Nokia Music, Transport and various other unnannounced stuff. It also gets the full WP8 tile screen (I.e. 3 tile sizes).
If your interest is speed then forget tech specs on processors and Google 'lost to a Lumia'. They are V. Quick....
E.g.
http://www.google.co.uk/url?sa=t&rct=j&q=lost%20to%20a%20lumia&source=web&cd=2&ved=0CFYQtwIwAQ&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3Dpq-CNCYNoKo&ei=gjDzT6lrj9nyA5CFoKoJ&usg=AFQjCNHKvxDGLMBS5MTyLsdLVgNjeSKskw