In my opinion, the best detector is the one you know how to use well and there are quite a few people who know the older detectors VERY WELL. I would also guess many of those people are somewhat resistant to change as well and I was one of those when I moved from the Eagle SL ll to the DFX. I hated the DFX for the first 30 days and it took me at least a year to learn the DFX well and I don't consider myself stupid to the technology either. The truth is, a lot of new technology has developed in the past twenty years in metal detectors and a certain level of learning is required to fully understand the features not only on what is available today, but wait until the next level of detectors hit the market, maybe within the next 30 days. If that don't blow you away, wait until next year and and the year after that and so on. With the speed of the new microprocessors and what they can do, doubleing in speed every few months, it will be only a matter of time before we will really be able to "see what is in the ground" before digging it.
The new detectors offer many new advantages and features that was not available just a few years ago and I think that if you take the time to learn the new detectors and how to best use them, you will benefit from what you will be able to find with them. A good example is a $4,000 bracelet I found with with the DFX. I really don't think I would have found it with the Eagle, and just that one find would have paid for three decked out DFX's.
The Eagle and many other older detectors work just as well as they did when new, but so does many older cars that have been well taken care of. Some people enjoy driving the older cars or using the older detectors, but the newer models of either has so much more to offer the user.