What seems to be developing as a theme to this thread is that the usefulness of a computer depends a lot on the type of diving you want to do. If you are planning a scuba holiday - recreational - with lots of dives over multiple days - then they are very useful. If you want to do a more complicated technical dive - then the use changes quite a lot. I haven't seen a single post that someone uses a computer exclusively to do a deco/cave/wreck (often the same type of dive) dive. While there are computers that are supposed to be able to handle such dives - nobody seems to want to use them for that purpose. Even though I'm not deco trained - I doubt if I would either! But for recreational dives - they are GREAT!