We migrated from Goldmine to Nutshell about 6 months ago and the difference is like upgrading from a VW Bug to a Ferrari. NS is a great system for B2B tracking of Contacts, Accounts (the Companies), and Leads (deals or opportunities). There is a Timeline tab that consolidates all of your notes and activities for each Account or Lead. The integration with LinkedIn (it finds and pulls basic data for Contacts automatically) and Gmail (will pull sent emails into the Notes section with a bcc: notation) is great.
Ideal for us is ability to create custom Tags to apply to any of the Contacts or Accounts, and then sort by them, and create Products and place a value and probability of closing so that we can estimate value of Pipeline and focus on the most valuable prospects.
We've not had issues with the bugs that some other report, although have made a few queries and suggestions to NS Support. We got immediate responses and explanations although have yet to see our suggestions implemented. My only gripe with NS is how it handles dates - you have to select them from a calendar - which is fine for dates in the near future. A date 60 months out requires 60 clicks - stupid, and why I deducted a star. In the grand scheme and considering all of the other customizable features, still better than the rest, I think. Just fix the dates, please.