I will just give all my observations on Nokia’s latest firmware release for Nokia 5800 since everyone with this phone is anticipating an update with significant changes… and indeed it brought significant changes particularly on the cosmetic side. 
So let me list down the things I’ve seen so far:
1. Kinetic Scrolling – This was apparent on the v40 firmware but not applicable to all parts of the user interface. This time, almost all of the user interface areas can now be navigated using kinetic scrolling. Of course, the scroll bar is still present.
2. Home Screen – There isn’t much change in the Home Screen options except for the Contacts Bar option which now features the same recipe as the one in Nokia 5230 and probably on 5530 XM.
3. New Music Player – Now, the music player displays Album Art on the music selection. It also has the music controls widget at the Contacts Bar Homescreen and displays the Album Art alongside.
4. Revised Text Input – Among the options, the full screen Keyboard was removed and this is because they made that feature accessible when you tilt the phone.
5. Changing Themes – When you view a theme, it doesn’t change the theme of the phone bit by bit. It slowly changes with smooth transition.
6. Improved Performance – well, others say it was very slow but for me, it was quite faster than v31… There’s probably one thing why at some phones, it is slow and this is because some countries have updates with a lot of applications to be installed. Mine just got that Ovi Sync, Ovi Store and Ovi Contacts. My internal memory displayed a significant change in free space, from 65 MB to 71MB.
7. Battery Life (either stable/same) – Some people said that v50 is a battery eater. Well I was about to believe it when after updating, the phone killed off one bar after a day but I’ve noticed that I was so fascinated by the cosmetic changes that I kept on opening the phone, using a lot of battery life displaying the screen, RAM for the kinetic scrolling as well as the vibration from unlocking the screen. I also opened videos but did not watch them and immediately closed them. Also for few hours, I did not notice that my phone was switched to 3G after updating. Now, at my normal standby operation with few texting, didn’t lose a bar after a day.
So far, that is what I’ve observed. They also said (including the change log from Nokia) that it punches a better browser but since I don’t use the phone as an internet browser, I was not able to check if there’s a significant change in that aspect.
Couple of worries though as my phone was emitting more heat from the battery than usual but that was right after the update. Right now, it is just the same as when it was running v31…
I think this firmware is way better than all of its predecessors. There’s no feature in here that made me wish to come back to v31.:D
i am using nokia-5800-xm-firmware-v50-0-005 but the apps opening takes more time .my cell phone fully slows down even i am havig internal memory 63 mb.
Really? I heard events similar to yours. What people in forums suggested was just reinstall the firmware to your phone. If you’re worried about the hassle of firmware flashing, what other people did was just did a reset of phone (*7370#). Back up your phone contents first before resetting.