In our time with the N97 Mini we experienced excellent call quality, with top class clarity and no problems with network handling. As mentioned, making calls is easy enough with the large touchscreen numberpad, while accessing and calling up contacts from the contacts phonebook is a home screen softkey tap away.
You can select contacts as favourites, which move them automatically to the top of your contacts list; others you can scroll through either with a bit of finger swiping action or by tapping a search panel and selecting characters onscreen.
One issue some may not like is that if you answer a call while you're using the keyboard, it automatically comes through the loudspeaker; it's not really a big deal, though, as you can easily switch to normal earpiece mode.
This phone is well geared up for those who want to do plenty of typing on a touchscreen phone. The texting setup is familiar S60 stuff, but the keyboard makes tapping out messages hassle free.
If you want to quickly type a message with the keyboard tucked away, that's no problem either - you can bring up a virtual phone numberpad by holding the phone upright, and this is spacious and sensibly laid out to maximise usability (unlike some touchscreen phones).
There's also a handwriting option that works OK. It's a pleasant experience all round, and we found the keyboard very usable.
As well as simple texting and MMS, the N97 Mini hits the spot for email. Using Nokia Messaging, its easy to set up the phone for web-based POP3/IMAP4 email accounts simply by typing in your email address and password, with the email client automatically taking care of the rest. Corporate email can be accommodated too, and the phone has Mail for Exchange support.
The email user interface looks good too, with options nicely laid out, and it's easy to manage your account using the on-screen options, and keep tabs on multiple accounts. Push email is supported too.
Nokia's Ovi Chat instant messaging service is available on the N97 Mini, with Ovi Contacts integrated into the Contacts list, while you can also easily add a Windows Live Messenger client for free from the selection of apps available via the phone's Ovi Store.