There are a number of well-known makes to choose from. The most popular and widely used is the Patterson system. Another and maybe not so well known is the German maker Kaiser no lesser a system. So what are the differences? When buying a universal developing tank, if cost is one of your main considerations the Kaiser system wins hands down as being very good value for money. So much so its worth considering if you are thinking of buying a Paterson second-hand.
Both systems have good and bad points to consider. Starting at the top in both cases I have found no matter how well the cap has been put in place it leaks slightly when inverting the whole tank. It can be a messy annoyance when using PMK Pyro as it stains whatever it drips on too. Yes I know that each system comes with an agitator but the Paterson one is difficult to use because it is so thin, unlike Kaisers which has a top to it you can grip and when turned also moves the spiral up and down in the solution as well. Each company uses a different way to fix their lids. Paterson's idea is a twist and click method which I prefer but can be miss aligned if you are not careful. The Kaiser tank has a screw top which I have managed to cross thread each time.
The Kaisers spiral design is the main reason that I have one of their developing tanks. I'm having trouble with kinking the film when loading 120 format onto Paterson spirals and have used lots of different ideas to overcome it. The main difference with the Kaiser reel is that it has two large feed in wings where you load the film which makes loading a lot easier and faster with no kinking. Because of the trouble I've been having with the Kaiser screw top tank I now use a Paterson tank with the Kaiser reel, it is a little loose on the centre tube but the C clip stops it moving up and down when inverting. So for now I have the best of both worlds.