Badandy,
I'm sure it's not the 152 mb memory you are talking about... I know not all of that is usable.
Perhaps it's the Samsung 2440 Processor at 400MHz vs. the 400MHz XScale PXA255 Processor that is used in the 4155.
The 4155 does have a better processor for videos but it's not a night and day difference.
Am I missing something? I still have time to take it back.
Benchmarks are from PDA Gold...
http://www.pdagold.com/articles/detail.asp?a=199