Contacts and contact management is generally good, however it lacks the finesse that could make it awesome. I find myself continually frustrated with what is a seemingly simple but highly important feature. I don't think I have seen a single deployment without a least 1 issue - Outlook integration, duplicate contacts, disappearing phone numbers, inability to search contacts added to custom groups, poor or hopelessly ordered search results - I could go on. These are small things, but contacts are so important, frustrations add up - Its probably my number one frustration with the product.
Microsoft please spend some time to fine tune this experience!