I installed my 10 Helix 2 weeks ago. I also have the 899 on the bow. No compairison in the 2 units. The Helix is much better. If you want to absolutely BLOW YOUR MIND, use the 'Autochart live' feature when you get it. I have re-mapped one of my local lakes and found stuff that I never knew existed. It is AMAZING!!! You keep it on your Chart view select on and start driving, the map "appears" as you drive.