Wow, I did the reverse of what you did. I left my Nokia N80 for a BB Pearl from T-Mobile.
At least in my experience, the N80 was...
1. Slow (compared to my Pearl) even though I flashed the N80 to the latest available OS
2. Always runs out of memory, whether I am using the standard browser that came with it or Opera/Opera Mini. Though to be fair, the N80 had 40MB of internal memory vs. the Pearl's 64MB.
1. Wi-Fi! 3G/UMTS (though I only get EDGE w/T-Mobile)
2. Ability to open and *edit* Word and Excel
All in all, I'm happier with my Pearl and can't wait for:
1. Pearl 2 w/Wi-Fi
2. DataViz to come out with Documents To Go for BlackBerry
Of course, to each his/her own.