QUOTE(allgentleman @ Jan 30 2018, 22:01)
how to decide the quality of an equipment?
like for rapier, except the Quality, it should be better with a Ethereal prefix and a Slaughter suffix, right?
for shield, is only block chance?
what about the heavy suit? and power suit.
how the IW 2 means?
ADB is attack damage bouns, right? The higher the better?
so hard to change the equips....
As a general approach, all builds want to be durable and do as much damage as possible. Anything that accomplishes that for you is better. Always keep that in mind first and foremost. Also, raising offense is typically better than raising durability. You need to be durable enough to not die, but once you reach that point, more durability doesn't help you as much. More offense speeds up how fast you kill things, and therefore reduces how much enemy attacks you have to endure.
Many people will try to tell you only about the best of the best. If it isn't 10/10, it's trash. Hopefully, I can help you see the underlying logic behind what makes equipment good, so you can figure out if a 9/10 gear is worth it, or if you even want to settle for an 8/10. They're all really good, but if you hold out for only 10/10 while wearing 2/10 gear, you'll have a harder time.
Some choices, like Magnificent instead of Exquisite, or Legendary instead of Magnificent are big improvements to your gear. You should mostly care about that before worrying about other details. A Legendary rapier of Swiftness is probably better than most Magnificent rapiers (except maybe Magnificent rapier of Slaughter). Quality tier improvements like this affect all stats of the gear, with simply better potential all over.
Slaughter weapons/power armor simply have more (usually about 20% to 25% more) ADB than non-Slaughter things. This makes them very attractive, therefore expensive. That said, a really low ADB% Magnificent of Slaughter is going to be worse than a high ADB% legendary of non-Slaughter.
Balance weapons and armor add a little bit to offense, but not as much as Slaughter. I wouldn't really treat them any differently than Nimble or Protection suffixed gear. Durability suffixes like Nimble and Protection are still of some use but remember the main point. Offense usually helps more, and most people can acquire enough durability without relying on suffixes to get to that comfort zone.
Prefixes on weapons and armor are mostly "if you have one it is better than not having one." When you get into legendary equipment, you'll always have one. Magnificent about half the time doesn't.
Once you're past the point where "something is better than nothing" then there are opinions on which ones are better and why. Such as the ethereal vs elemental weapon prefix. Other cases it is much simpler: Savage prefix on power armor raises critical damage a little bit, which is more than any other power armor prefix (which add only to durability).
Your shield follows a similar, but slightly different, set of considerations. Force shields are better than Bucklers with the "Barrier" suffix which are better than Kite shields which are better than other Bucklers. This is due to how much block stat the shields have. Higher BLK% stat is the main thing to look at. Wearing a shield is the privilege of the 1h build, and the main point of the shield is how much block it gives you, raising your durability a lot, but also increasing your offense through counterattacks.
Shields are also a little strange in that there are four PABs that can be on a shield: STR, DEX, AGI, and END. But only three of those four. There is a small preference for STR+DEX+END (usually referred to as SDE) because AGI is practically useless for the 1h+heavy build. If you have a shield with AGI on it, pretend it has a 0 for that stat, and treat it as simply having less than 3 PABs. A Legendary shield with high block but "missing" a PAB is better than a low block shield with three.
After that, some people prefer certain prefixes or suffixes, but they all add to durability on a shield, so we're mostly arguing over tiny fractions of importance at that point.
Overall, there are lots of little decisions you could wind up making. "This is better than that." Almost nobody will tell you "this is 10% better than that" or "this is 50% better than that" or anything that detailed, so it is easy to get the wrong impression that you
have to only take the absolute best.
Just look at any two pieces of gear, and see all the different things that one is better at than the other. You might see two shields with very similar stats, but one has higher STR and the other has higher END. It's up to you to decide which is more necessary to you and by how much. As you compare lots of pieces of gear over time, you'll tend to learn which differences are so small you ignore them, and which ones really matter.