[Michael R 1974]

Instead of preferences, let's just lay out a few characteristics. They can be seen as pros and cons, but really there are ways to work around each.

Plastic/Paterson
1. Sometimes the lids leak a little ("burping" the lid seems to help)

2. Much faster fill/dump times than SS - ideal for uniformity

3. More parts to break/crack

4. Plastic reels are often cited as being more prone to air bubbles

5. Plastic reels can be difficult to load wet (remedy - dry them)

6. Assuming all parts are plastic, no problems using selenium toner etc.

Stainless
1. Durability (the older Kinderman stuff at least) - I'm still using the same one my father bought in the early 70s. This may not apply to current systems. The cheapo Chinese tanks are thinner, often with the bottom being a separate piece of metal, and the lids do not seem to fit as tight.

2. No leak problems (subject to quality of lid)

3. Relatively slow fill/dump times through the daylight lid. It's ok for small tanks, but particularly for a tank any bigger than two-reel capacity I would strongly suggest filling the tank first, dropping the reels in and then putting the lid on.

4. Good reels (Hewes, Kinderman) are a breeze to load - even wet. Although I still don't know why anyone would load dry film onto wet equipment.

5. SS will conduct heat from hands more efficiently than plastic. Several easy remedies - tempering bath, wet hands in cold water before agitation cycles, grasp the tank with balled up paper towel between hands and tank, gloves etc.

6. SS may or may not cause problems for things like selenium toning of negatives. I don't have a definitive answer on this. But worth thinking about particularly with cheaper, lower quality SS.

So, obviously you can use either and get the same results in the end. They just work a little differently.