I use PMK exclusively for my own work and for 90% of my B&W lab clients. I've used PMK for at least 5 years. Here's the advantages I have come to take for granted.(posted 9291 days ago)1.The negatives are much easier to print. Exposure times, where they differ at all, are a little shorter than those negs processed in 'normal' developers. Highlights are easier to print with texture. (In fact, using 4X5 Delta 100 or the new Bergger BPF200, Zone VIII is fully textured and there is some texture extending well into Zone IX!)
2. The longer than 'normal' development time (av. 15 min.) ensures even development. I don't trust a developer with times of 5 minutes or less.
3. The keeping properties of PMK are incredible. In fact, I keep 2 or 3 liters of 'A' solution to 'age' in a gallon jug with a natural cork. When the 500 ml of 'my working stock' part 'A' runs out, I refill the bottle from the aging solution and make up another 500 ml of fresh 'A' and put that into the gallon jug. Because I buy pyro by the pound (!) and mix from stock chemistry, the cost per use is litterally too small to consider. A fairly busy hobbyist or semi-pro will run out of stock long before it goes bad (if it ever does.)
If some of you are experiencing longer printing times and little or no difference in highlight contrast, I believe you may be over developing your film. Because a properly exposed and developed PMK negative looks thin and flat to the eye, some may extend the development time to get negatives that look more like those developed in 'normal' developers.
I will repeat the advice from a previous response, get Gordon's Book of Pyro!!! It's just $30 and the information it contains will save you letterally weeks of experimenting.
Most of all, don't give up. A new process, especially one as different as PMK developer, will inevitably have a learning curve. Just know that in the end, it will be worth it. (Every had piano lessons??)