You also don't have to go with one of the big name products, it depends on what you want the system to do.
Best to start with what you need, then see if you have the budget for what you want. All the fancy weather overlays and airport minima alerts are nice to have but not essential as you can do this the old fashioned way.
There are other cheaper systems out there if you just want to see where your aircraft is and be able to call them up in-flight and send/receive basic free-text messages.
Harrier is one, so is Blue Sky Networks, they run off a satcom feed however. You can go light and use a portable unit (mixed results with that but setup runs at a couple of thousand dollars) or you can go integrated and get the antenna and avionics installed on the aircraft, much higher (partially because of the STC requried) cost but golden result. Bluesky offers neat XML feed so you can see what's going on using Google Earth.