Joystick taste is so darn subjective. What some people love about a joystick, others hate. I have had cheap chinese joysticks that I liked better than nice ultimarcs before.
For classics, I am gonna be the purist and sit on my evil throne of purism (and skulls n' stuff) and say that you can't beat a wico leaf joystick. Of course you can't get them anymore, unless you get NOS or go with used. I still love the wico leaf stick. I've been meaning to try the GGG leaf-pro to see if it compares, but haven't had the funds. If anyone has insight on leaf-pro vs a wico, I'd love to hear it.
For newer games, and fighters, I love my JLF, it is amazingly light and floaty. Real elegant. It really isn't ideal for the classics. Most people here will go with a JLW above the JLF though. It is a much more well rounded all purpose stick.
A lot of people love the mag stick, but it is a little too stiff for my taste. I think that is a European style thing. One the flip side, I think I would love the servostick, but haven't tried it yet. It can be set to automatically adjust A lot of people love the 360 as well. I have never heard of anybody hating the 360, but I have heard of people being a bit underwhelmed.
I was going to put the 4 way in the center and I noticed that some of them appear to be switchable on the fly but I don't know enough about them to make a good decision. Is it worth it to have a switchable and can they do it on the fly based on game? For example if I go from Mortal Kombat to Donkey Kong?
For manual adjusting, Ultimarc has the mag stick/ mag stick plus is manual switching. Mag stick has a lever in the underneath you switch, but the plus you can just do it by lifting and rotating the stick. GGG has the omni stick/ omni prodigy which has a lever. The reg omni is underneath, the progidy is on the top of the control panel. My opinion is that it is totally not worth getting an underneath adjustable these days.
For auto adjusting, the 360 and servo stick from ultimarc are the ones I am familiar with. The servo stick will adjust a physical restrictor plate that will adjust based on game. The 360 is only a software restriction, and you can set different "maps" that will tell the joystick how to act based on game. The 360 is a analog joystick, so you can also use it for analog games as well.
In my opinion, if you are not particular about the EXACT 4-way joystick you want, then don't add an extra joystick to you panel. It just makes for more clutter and more confusion when playing with friends. If you find a switchable you think you would like, go for it.