After trying the software on my Nokia 5800 for some time I'm really impressed with the software and the service Nokia is providing.
Though some 'must have' features like html, graphical notification etc are missing. I'm sure these features will be taken care of in the future releases.
The feature that I'm really looking for is the ability to show attachments (like ms office, pdf and other popular docs) in simplified html format. With this feature, Nokia Messaging will immediately stand out from rest the mail clients. Users will be able to see attachments quickly. No need to download and manage/sync the downloaded attachments. No need to look for different viewers. I hope Nokia will consider including this feature. After all, we are using our mobile phones to quickly view new mails and reply. Managing emails and attachments is still better done using pcs/notebooks.
[A Datta]