Is there a decent, fully featured client for Exchange Server 2010?

We have Outlook 2011, but it lacks functionality and things are a little screwy - listing contacts by surname has them appearing in random order (I'm going to try repairing the mailbox database later, when I get access to the machine).

I've set up Mail/Calendar/Contact on my iMac, but that misses out on a lot of features, such as notes, to do lists etc. that my boss uses heavily.

No.

Outlook 2011 isn't great at all, I use it but quite often end up running Outlook 2010 or 2013 in vmware fusion

Thanks, that was the conclusion I had come to. It won't make my CEO any happier though.