Tim: You are right about knowing which train to catch and when to jump on. Holding off on the ADS-B decision has been made easier for me since it is not well implemented on our area, as far as I can tell. I am so glad I boarded the AP iFly train when I did. In retrospect, that was a very good decision. One other very popular manufacturer has a strategy of planned obsolescence, it would seem, by their policy to discontinue support of units when they reach 5ive years old, and they have outrageous minimum charge repair fees, too. You don't know this when you purchase their units, but the word is starting to get around. The flying customers are catching on and choosing to purchase well supported products, like the iFly. It's just hard to know which vendors are going to stay in the game when you are an early adopter. Two things are certain, technology keeps leapfrogging by orders of magnitude, and usually the technical capabilities increase for the same price. A friend of mine observed, somewhat tongue in cheek, that 20 years ago Oshkosh was about airplanes, now it's an electronics show. 
We wonder what new gadgets will be on the market next year to make our flying even safer and more efficient? Should I wait or jump in the pool now? I am very happy to have "the latest" technology in the cockpit - no question but what it can really enhance safety - but every now and then, just for the pure enjoyment and practice, on a good VFR day I like to shut off all the navigation aids and fly to a destination using pilotage and dead reckoning, like we did years ago before we had "highways in the sky" and GPS. For me, that can be as personally rewarding as shooting an IFR approach to minimums. (But only every once in a while). ===Ralph