Make sure that 499 model is chirp. I have had the chirp and non-chirp Garmin 73sv. I have only seen the non-chirp model at 499. It will say chirp in the name if it has it.

They both perform well on my boat. I only upgraded to the chirp version for the future possibility to use panoptix and also adds extra networking capabilities.

I really havent been able to tell difference in the images.