i own both of it.
VS 
Nokia 71 Pros
Very fast processor same speed with 5800 XM
Gps lock via garmin is faster than 5800 XM
Many symbian software and game available because its running on S.9.3
Looks modern and cool design
Body Build very solid
Two home screen for home and office
Amazing Physical QWERTY keypad abit small but acceptable
Comes with nice pouch
Cons
Screen too small
Radio Doesnt support RDS
speaker quality average
Cant use 3.5mm earphones
Screen only 2.36 when E61i is 2.6 inch
Light notifcation not obvious
5800 XM Pros
Big screen
4 Input method Handwriting,Virtual Qwerty, Mini virtual qwerty and alpha numberic
Acceptable Stereo Speaker
Support RDS
Fast Processor same speed with E71
Gps lock is fast but E71 is faster
Auto rotate screen auto rotate silent
Support Photo and Video Geo tagging
Support many future Accelerator games
Auto proximity sensor turn off
Cons
Due to new OS software and games are very limited
Very Disappointing camera output for a 3.2 megapixel carl zeiss and E71 take better photos compare
I will choose 5800 XM for the big screen.
Wow..thank you so much for the information.