I spent a lot of money to install Simrad on my boat. 6 months later I spent a lot of money to remove it all. There was a long list of things that did not operate as advertised, and Simrad was unable to fix any of them, or even provide a plan, commitment, or date to fix any of them.
It's coming up on three years now, and I don't believe a single one of the reported issues have been fixed. So I would not buy Simrad, and hence would go with Garmin.