If you're going to do mostly digital (4 & 4 way) games, I'd suggest a restrictor to shorten the throw and give a "harder" limit edge. I'd go for the circle restrictor (aka, have it) over the octagon one, but choose whichever one you like the feel of. I don't have the octagon one, but it's supposed to have the same throw as the circle, except you can feel the corners & cardinal directions. For analog stick games, I prefer no restrictor, so I have joy 1 with circle restrcitor and joy 2 without (and mapped to player 1 in analog stick games), ATM.
So how is everyone dealing with the new auto-mapping mame settings:
joystick_map
joystick_deadzone
joystick_saturation
in regards to the u360? I would think you only want to tweak map settings in one place; either hardware with the u360 maps, or in mame software. But not both. Please advise.
First off, make sure the ultrastick software has the sticks that have restrictors to restrictor mode. Then, if all you're going to play is mame and haven't set up the fatfingers app, I suggest just using mame's maps (this is what I do). OTOH, if you're going to use other emus/games, or already have the fatfinger app setup, go ahead and use that app and forget mame's -joystick_map option.
Okay, if you're going to use mame's options, set the u360 in analog mode and leave it there. Mame's options -joystick_deadzone and -joystick_saturation are mostly for analog games, but they effect the mapping too, especially the deadzone one. I've left the saturation at default, and decreased the deadzone to 5% ("joystick_deadzone 0.05" in mame.ini). I'm also using the default maps, which AFAICT the same as u360's default maps.
If you want to see what map mame uses for different games, enable -verbose option to see what mame prints to the commandline, and start an 8-way and then a 4-way game. More info on the options are in mame's docs/config.txt than I'd like to repost here, but if you have any questions, I'll be glad to help.