I have the same issue. Inbox hangs at "Updating" from 30 seconds to 2 minutes intermittently before the Inbox appears when trying to view messages. I have from 5 to 6 messages in my 2 different Gmail Inboxes.

I tried removing my Gmail accounts from Nokia Messaging and just had Nokia Messaging use a new Ovi Mail account I created and a Yahoo Mail Account with about 10 messages. Same issue.

I deleted Nokia Messaging from the phone and just setup my Gmail Accounts via IMAP with out the Nokia Messaging account on the phone and it seemed a bit faster, but there was still about 30 seconds hanging at "Updating"

The Issue is present either by using Nokia Messaging or IMAP.
The issue is present either on WiFi OR using 3.5G via T-Mobile USA.

I'm quite surprised that I don't see many posts about email client issues.

I did find a thread specifically regarding users using IMAP and having tens of thousands of emails in their Inbox causes the email client to crash.

But like I stated above I do not have tens of thousands of emails in my Inbox and therefore my email application doesn't crash it's just extremely slow and almost unusable on the go at times.

The following thread has a link to a bug report specifically addresses "IMAP accounts with a large number of messages in one or more folders (e.g. INBOX)"

maemo.org > Talk > OS / Platform > Maemo 5 / Fremantle > Any solution about the issue on Gmail an large database of Email?

http://talk.maemo.org/showthread.php?t=35191

The bug report is tagged as fixed due to a fix already in place for the next firmware upgrade.

I tried doing several searches on https://bugs.maemo.org/query.cgi

I am unable to find any bug report specifically addressing slow email client performance.

I will need to do more testing and if it's not resolved I will find out how to properly post a bug report to make sure issue is addressed.