One of the interesting things about AT is that it allows you to boost your main combat stats directly during any given level up. Because of this, you can use "1 level" as a very good measure of determining which items are better than others. Some of these will come as surprises.
The system I use is simple: you can get any of 4 stats during a level. Either +5 Attack Chance(AC), +1 Attack Damage(AD), +5 Hit Points(HP), +3 Block Chance(BC). So when I determine an item's quality, I measure it in levels.
Then there are the "unlevelable skills". These include Damage Resistance(DR), Critical Skill(CS), and various Status Effects
Following is full of spoilers. I am going to show which items in each category are best by this measure. I am not going into weapons. That's a treasure trove of different effects, and requires considering AP, which I won't do here much.
Rings: