Well its pretty easy
1) A bow without good SSI practically isn't useful at all. Even with great mods, a bow without more than 10 ssi isnt going to do much for you if it isn't fast. A average bow hitting at 2x the speed is more important than a great slow bow.
2) 3 properties are considered very important on a bow. If you have them its a huge benefit.
Hit lower defense. Hit stamina leech, and Hit lighting or fireball. These bows are not only great for PvP, but for PvM.
3) Hit mana leech is greatly desired in a PvM bow.
Then you have certain properties that benefit you, but aren't found much of the time. Velocity and Balanced. It all depends on the bow. Many here can give you hints on what are nice and what are junk.
Don't forget, other properties don't mean a whole lot unless the bow has SSI on it. Why have a heavy xbow that you can shoot every 4 seconds when you can have one that you can shoot every 2ish seconds.
Lets say you make a heavy xbow with..
50 hit lower defense
50 hit lower attack
50 hit lighting
1 fc
40 damage increase.
So, how good is this bow? Yea thats right, not that good. Why? Even though it has great mods on it, it doesn't have any swing speed increase, making it super super slow. What good is all those mods if you are getting creamed by monster spells, melee damage, etc.
Now, lets take a Heavy Xbow
50 hit lower attack
30 ssi
40 damage increase.
How does this compare to the first bow.. Really only has a couple mods, basic bow, but many would use it over the first bow. Because its faster.
How about this bow?
Spell channel
mage weapon -20
30 hit mana leech
Doesn't look like much, but hey! thats a amazing bow! you are lucky enough to have some properties that make it a great bow for a mage. You don't need any skill to use it, and while you have it equipped you can cast spells, and do a tad more damage, plus the mana leech will give you back a tad bit of mana over time. A nice bow! Great for any mage to have as a 2ndary attack method. I use a bow like this for peerless. I can cast my spells normally, but have a bow going at the same time. And dont' need any extra skills to use it!
