A. Power rings are tricky. The green power rings are relatively free of unwanted side effects, but they come with the caveat of you are at the beck and call of the Guardians. That's not a huge problem for me because I am a team player and do not mind taking orders from someone smarter than me. Ganthet is a dick, but the other Guardians are reasonable people.
The other power rings, have a lot of nasty side effects. Maybe the blue ring would be okay, but I'm too pessimistic to use one. Well indigo rings are okay I guess. I probably have more compassion than willpower, hope, avarice, fear, anger, or love. I've never seen a television show or comic book with indigo rings in it so I have no idea how they organize themselves or what they do. The Indigo Corp is the least developed least interesting group.
Power ring is first choice because I could theoretically use it.
B. WIthout all of Bruce Wayne's advanced training, the Batsuit is just a costume. I guess it's counts as armor. Unlike the other items on the list, this is the only one that won't get me killed. Unless the Joker is real of course.
C. But speaking of armor. Iron Man's suit is the best. But assuming you don't break your spine in a flying accident, you are screwed the second you need to repair something or perform maintenance. WIthout being friends with Tony Stark or being Tony Stark, you cannot use it for long.
D. Speaking of not being able to use it...Moljinir only works for children of Odin. I happen to look a lot like my father, so I'm pretty sure my mom didn't fool around with Odin behind his back.
E. Captain America's shield. This is the only item on the list that doesn't have side effects or require advanced training. But there are very few situations where I find myself thinking "I wish I had an indestructible shield!"
F. A symbiote is self maintaining and requires little if any training BUT it comes with a substantial loss of freedom. It's still my third choice after power ring. It's a gamble, but if my symbiote isn't a horrific monster I could come out ahead.