I don't know about Dediprog, but can say a few things about Aardvark.
Pros:
-Works in windows and linux
-kind of just works
-good for commanding SPI and I2C devices with PC, not just memory programming
-separate memory programming tool for easy memory programming
Cons:
-not quite hobbyist price
-their software download is extremely annoying for a device that can be bought by anyone
Vintage? Aardvark is only good for SPI flash chips (and I2C, but they usually are not used for firmware storage on motherboards). Not going to work on regular BIOSes that have parallel address/data buses.
Also, while Aardvark is good for embedded systems developement and thus worth the money ($300), anyone could make a SPI flash reader or burner out of a Arduino or similar that costs less than $30 and few lines of code.
Aardvark comes with a clamp nowadays? Back then it didn't and clamps that were found were either super expensive or just so poor they were unusable.
Also, you don't need to give your email when downloading, just use one-time webmail services. But really, a device that can publicly be bought by anyone should just have drivers and software available with a single click. I would understand the download policy if it was some super secret device that can only be bought after signing an NDA or some other licence agreement so that the software can't be downloaded by anyone (hackers, competing companies, etc).
And, it's possible you could not read the SPI flash chip with Aardvark, because it was still connected to the motherboard chips. You cannot expect things to work when two masters are connected simultaneously to same slave, unless you are sure the motherboard releases the bus when it's idle. More generally, two digital outputs connected together simply does not work.
