Ron and Others,
I had the chance to view John's SRF-39FP digital display (from aade.com) in action, this week at Grayland, Washington. It was very impressive, but when the $$ are added up, it may not make much sense to purchase it, except perhaps as a curiosity.
For domestic DXing purposes, the SRF-59/39FP analog family of units provide tremendous "bang for the buck," but not when combined with a $69 add-on accessory. I'm sure John would agree with me that a better solution would be to purchase a digital E100 or DT-200VX, and save the cost of the digital conversion. Either of these units can be purchased for less than the cost of converting an analog SRF-39/59 unit.
For split-frequency DXers, the SRF-39/59 family of units is easy to modify for increased sensitivity, but their bizarre IF makes conventional narrow IF filters useless, and useful selectivity mods have yet to be designed. On the other hand, the digital Ultralights (with their 450 and 455 kHz IF's) can all be modified for increased selectivity AND sensitivity.