It is a huge upgrade in graphics, programming, sounds, rechargeable battery and dock, more buttons, bigger screen, etc.

The only things I can think of that may be advantages to the 450 are programming on remote and doesn't need software, easier to learn and possibly some might prefer it ergonomically.

My guess is who ever had it found the programming difficult compared to the 450. It is not really more difficult but with added functions in programming there is more complexity and will have a longer learning curve to get proficient in the software and learn all the more you can do with it. However, once you understand the software it can be much quicker to program unless you do a lot of custom graphics and sounds.