There is no question that avionics systems like the Garmin GNS 530 have captured the fancy of many pilots. I have flown some of the other systems and found them quite capable, but the 530 is what resides in my avionics stack, so it is the most familiar. Other systems can be used in the same ways and for the same things as a 530-the difference is mainly in presentation and organization.
One of my first impressions when I started using the 530 was that it is almost the only piece of equipment in the avionics stack that I use on a regular basis. It handles all the communications and all the navigation, with my other two (three if you count handhelds and four if you count older navcom sets) navigators serving in a standby role or displaying information that I am not showing on the 530. The 530 is also a lot like a personal computer in that it will do many things in a lot of different ways and pilots will use it in different ways. Call it a personal navigator, plus, if you will.
I had a thought about this while flying along. The last time I had an avionics system where one unit served as primary was in my Piper Pacer, in the 1950s, when a Narco Omnigator was numero uno. The Omnigator had a comm transceiver, did VOR and localizer functions (nobody had a glideslope at the time) and had a marker beacon receiver. There were other radios in the panel, but the old Omnigator did most of the work.
Narco advertised that the Omnigator would fit into a standard glove compartment, so it was about the same size as a GNS 530, except the Omnigator required an enormous power supply stuffed full of vacuum tubes and transformers. That big box usually got stuck in the baggage compartment. The Narco had a whopping eight-channel transmitter, and it was said to be the most accurate VOR receiver on the market. The Omnigator weighed 18 pounds compared with 8.4 for a GNS 530. It was accurate enough for IFR flying, and I used it for just that.
At that time pilots were having as much trouble learning to use "omni" as some say they are having with GPS today. Fifty years ago, my father, Leighton Collins, wrote in his Air Facts magazine about the Omnigator. His piece started: "It is easy to imagine some fellow getting a new Narco omni set installed in his airplane, getting out and getting hopelessly confused, and coming back and saying it is no good." Then, in 16,800 words he explained it. That it took that much space to explain something as dirt simple as an Omnigator says it all about pilots and new equipment. His words about the pilot saying it is no good because the pilot was confused have strong parallels to GPS today, as some whine that it is too complicated.
The new avionics are not complicated; it's just that in a system like the 530 you have a device that does so much more and presents more information than was available from all sources when I was flying with that Omnigator. The 530 also does a lot more than the avionics it replaces in today's panel. The challenge with a 530 is to get it set up the way you like it and use it in a way that gets you where you are going and that pleases you most.