I should have read your title and realized you were looking for a Sonar/GPS combo unit. I thought you were looking for a dedicated sonar unit thus the Furuno recommendation.

The A50D appears to be a nice unit. My dad runs a digital RM sonar on his boat and is very happy with it as is Frank S who posts here frequently. They work very well!

Two concerns:

1) The viability of splitting a 5" inch screen. Alot of buddies have tried this and were unhappy which resulted in them buying a second GPS or sonar.

2) I could be completely wrong here...but Raymarine is struggling financially and very well might go "belly up" in the near future which could affect the warranty, customer service, etc.

Good Luck-