I have a 360 on mine. It is a potential failure point but is also more comfortable. I was advised that there are a lot of junk swivels around. The real OmniSwivel is supposed to be a reliable swivel but at $82 each it is a bit steep for me. I was advised by a person I trust on gear, of a swivel that is only $25 and has served them reliably over hundreds of dives. You can buy it from Cave Adventures or Deep 6 Gear:The ball-swivel vs. elbow and which angle is an oft-debated topic from what I've seen around here.
Cave Adventurers - Swivel - Marianna, Florida USA - Never Undersold!
I cant find the Deep6 link but maybe @cerich can link it
I view the OmniSwivels as disposable. When you service your reg put new ones on because you can not see the state of the internal O rings. At $25 each I am ok with that.