I can speak for Diafine. Diafine is a two solution developer that can be used with most any film. It comes in two cans of powder that need to be dissolved in water. It's primary feature is it's consistency of results independent of time, temperature and agitation. As long as the solution temperatures are between 70 and 85 F, developing times in each solution are between 3-5 minutes and agitation is once per minute for 5 seconds, the results are very consistent. Film speeds are typically boosted 1/2 to 1 stop, per the instructions.(posted 9125 days ago)You can not do N+/- development with Diafine. My experience is with Tech Pan, T-max 100 and HIE so far. The negatives have a full scale and the results with Tech Pan are the best in 10 years of Tech Pan use. With Tech Pan, you must develop in the "B" solution for exactly 60 seconds. Other wise, temp, time in the "A" solution and agitation are the same.
I discarded Microdol, Ethol TEC, Rodinal, Technidol, and T-max developers last year and am casting my fate with Diafine for all B&W development.
I got a first prize last week for a HIE print souped in diafine and the judge commented on the beautiful range of tones in the print. Many consider Diafine a meat-ball type of developer, but so far I'm extremely pleased with the results. I've develop almost all types of B&W film in almost every developer (including some home brew) over the last 45 years.
YMMV.