As the normal saying goes, it's whatever value you place on it and to be totally honest, this one does have a wide range of opinions.
This particular machine has polarized views because purists believe this to be a desecrated Macintosh 512k (or 128k) and value it less than a normal 512k. Some, (like me) feel it's actually pretty cool because it is one early example of Apple needing to make an exception to their policy on unauthorized upgrades to their computers. I've read that some at Apple even used them internally before they allowed this upgrade to be accepted and supported. It also appears to be actually rare because I can count on one hand the number of working HyperDrives there are here (that I've been able to find). That said, to me it's no where near $900 (like in a particular auction at the moment) or even half that for a Mac 512k. A HyperDrive Mac 128k? I don't know what the 512k upgrade that is included with the HyperDrive looks like but if the original Mac 128 board is not touched, it could be near that price for someone.
With that said, if you are in the purist's camp, I did take one of these 512K's apart, as noted in my recent thread, and moved it to another 512k and it is totally reversible without any hint that it was there (there are two solder points to the analog board). The only issue will be the lack of uniform yellowing underneath the extra HyperDrive labels
The HyperDrive upgrade is an oddity. You either love them or hate them. Hope this helps a little.
This particular machine has polarized views because purists believe this to be a desecrated Macintosh 512k (or 128k) and value it less than a normal 512k. Some, (like me) feel it's actually pretty cool because it is one early example of Apple needing to make an exception to their policy on unauthorized upgrades to their computers. I've read that some at Apple even used them internally before they allowed this upgrade to be accepted and supported. It also appears to be actually rare because I can count on one hand the number of working HyperDrives there are here (that I've been able to find). That said, to me it's no where near $900 (like in a particular auction at the moment) or even half that for a Mac 512k. A HyperDrive Mac 128k? I don't know what the 512k upgrade that is included with the HyperDrive looks like but if the original Mac 128 board is not touched, it could be near that price for someone.
With that said, if you are in the purist's camp, I did take one of these 512K's apart, as noted in my recent thread, and moved it to another 512k and it is totally reversible without any hint that it was there (there are two solder points to the analog board). The only issue will be the lack of uniform yellowing underneath the extra HyperDrive labels
The HyperDrive upgrade is an oddity. You either love them or hate them. Hope this helps a little.