Good is an absolutely horrendous app. Awful.
Ugly and clunky interface, I can get over that. Incredibly slow development pace, so features like TouchID or iPhone 6 resolution either never come or take months/years. Even the slow syncing. All a nuisance, but not a killer. But the Contacts functionality is far and away its most irritating weakness.
If you sync with Good, you can't back up with iCloud or any other syncing option (I use Outlook.com) to work across devices (ie home computer). I understand the security requirements of the encrypted email service, but not being able to sync my Mum's email address and phone number seems to be a solution to a non-problem. If you make the choice to sync with Good in order to have your contacts available to your Phone app, then you face a number of issues.
The labels for the contacts don't work properly in many cases (mobile, Company, etc.) across your Exchange contacts and device. And, contact pictures don't work. Ever. However, the biggest issue? Duplicates. The app seems utterly incapable of not duplicating contacts when changes are made to contact details.
All in all, a great idea that fulfils the needs of the IT function and infosec requirements, But dreadfully executed from a users perspective.