There are a lot of good developers in "The Darkroom Cookbook". having tried a few of them, I would definitely disagree with the statement that "there is often little to differentiate paper developers". Even with MG IV RC the differences are obvious - at least when comparing otherwise identical prints.

All great fun - and the ability to mix up a small portion for a special purpose is worth it all to me.

Maybe too much fun - I've used more different developers in the last 2 months than in the preceding 15 years!