I use a MOD54 insert in a Paterson tank and it makes processing 4x5 very easy, particularly if you want to use techniques like stand development. The whole thing is no more complicated than processing a 35mm film, although I tend to limit myself to four sheets at a time, not six. A slightly more gentle agitation is required but I haven't had a film jump out of its slot yet.
If I want to process more than six sheets then I have a Yankee developing tank and filling it with 1600ml of developer becomes more economical. Despite the bad press some people give it I can't find fault with this tank, except for the volumes required. It is very easy to load and following the instructions of swishing from side to side in the correct direction I get evenly developed negatives. But, because of the slow filling and draining of the tank I do make sure to use it with slow developers.