I had the SGX for a few years. It worked well... the course I was a member at during that time had smallish greens, so front-center-back approach distances weren't an issue. I just most always played to the center of the green yardage.
But I started having issues picking up the Satellite for the unit, returned it, they gave me a refurbished unit as a replacement, and it started having issues too.
That was around the same time that range finders started becoming popular, so I've owned a Bushnell V2 ever since.
The annual fee was definitely a downer for me. Not to mention that back then you had to go through a tedious process of downloading courses onto the unit to use it.
Garmin seems to be the preferred unit these days. Look forward to hearing how you get along with it.