I purchased the Garmin 545 last fall. I liked it because it was small enough to mount at the helm but the screen was big enough with high enough resolution to be able to read (I am old enough to need all the help I can get). I did not get the sounder sensor, as I have a reliable depth sensor in my other equipment pack. I used the Garmin extensively in bringing our 35' sailboat from CT to NC last year. It comes with all the coastal maps installed and I found them accurate (even getting into and out of Rock Hall). It worked very well and after a few days I was pretty comfortable with using it with waypoints, etc. It is pretty easy to learn, but has a few annoying quirks (that I cannot remember at the moment!). I mounted it using an adjustable (universal) rail mount (RAM, I think) I found at WM. It clamps to the guard rails around the pedistal and holds the Garmin mount such that I can pivot it up and down and swivel it side to side. You can see the mount arrangement on the left side of this picture, the Garmin is not there but it sits right in the middle between the upper NavPod and the lower instrument pod, next to the compass.
Its a good location, for me, out of the way, yet readily visible. I will eventually replace the Ram mount with a fixed Edson mount once I figure exactly where I want it. That will also require machining some sort of adapter to maintain the flexibility I now have; that's project #1836. Right now this works!
I have had no issues with the unit, I hooked up power and it worked and continues to work just fine. As I mentioned elsewhere the data (tracks, waypoints, etc) are stored on an SD card and there is no direct computer connection to move that data to another computer. I used a hand held Garmin that had both the SD and the computer connection to transfer the data. But perhaps just an SD card reader might work as well, if you Garmin's MapSource for the other computer.
I considered units that would connect to radar, etc, but they require a bigger screen to see all the information and I just did not want that big of a unit at the helm. Maybe when I can afford another chart plotter at the nav station, I will looker into the bigger screens. I did look into the 3200 series units at the time, but I think they were being replaced with these small foot print 500 series as the screen size and resolution are the same.