To me its one one of those "character in the flaws" thing. I bought one brand new when it first came out and you'd probably have to pry it out of my cold dead fingers to get it from me. It almost sounds analog compared to susequent versions. Plus its built like a tank. Mine has been put through hell and still works. The newer ones just feel cheap. I've also heard that the company that built the original software/chip went under and digitech has never fully been able to replicate it. I also read in an interview with Tom Morrello that they are difficult to repair so he buys them whenever he finds them. The original is amazing, but definitely an investment and collecter's item.
Having said that, it seems that digitech has finally made something close to the original with the 5. Plus it has midi control and a chord shifting mode. I might actually get a 5 and save my original for home/recording.
I like the new one too, but here;s some info from our FAQ:
Why does everybody seem to prefer the old wh-1 Whammy over the others?
The Whammy II had redesigned "improvements" made over the original whammy when it was released. The biggest mistake was putting the input gain control in there - if you don't get the adjustment "just right" then it will not track the input pitch properly and, even if you do get it right, as the input decays the pitch tracking will eventually lose its "lock" on the signal.
The original WH-1 Whammy had a special circuit that the Whammy II does not (thus no "input level" control), allowing almost any input signal level to be dynamically scaled so that the pitch tracking can "lock on" faultlessly. This also meant that as the signal level decayed, the pitch would remain locked due to the scaling action. The Whammy II loses lock on the signal as it decays, resulting in a highly unpleasant "warbling" sound which you may have noticed if you've used one.
Why was the whammy modified?
The old red Whammy was probably changed because it was quite expensive and not selling as well as it could be. On most newer mass-marketed pedals, the price/cost is the main feature. In reality, the Whammy-II ended up costing almost as much (and even more in some areas) and people didn't like it nearly as much. It had some cool features (you didn't have to bend down to change modes, and it had the "toggle" feature to switch between your two favorites) but it did not SOUND the same, and it was a little less robust than the original version.
How about the reissue whammy?
It seems that they did not use the exact same algorithms as the original so they still don't sound quite as good. The original manual has a note Copyright 1990 IVL Technologies Ltd, looks like they were the ones who designed this pedal for DOD. You can find the manual on www.digitech.com.
After this FAQ was written, the current 5th generation came out and I think it's great.