1 big difference: stability
but i guess if you're not working with huge files,
you wont fall victim to the bugs. one of the most viciouse bugs
is when you save a huge file (with many channels) the program will go through
the motions of saving, but it will really just dump your work out,
leaving you with the exact same file you started with.
i fell victim to that on BIGTIME, and lost alot of$$$
5.5 is the most stable version i think.
never crashed on me. just lacks an expanable history pallet, some
filters like liquify, but who needs that junk?