Hey Dew and Fish,
It's a lot of things you two are asking (and pretty understandable)
First damage and armour stats.
Simply put, the higher the better.
After you reach level 40 your power will be measured in Light Level, this is where the yellow numbers come into play. Your Light Level (LL) is a total of all the yellow numbers you have (weapons, armour, artifact, class item, and ghost shell)
The Damage stat is not related to the LL of the weapon, it just shows how hard it hits (stagger). If you look closely you'll notice that most weapons follow certain archetypes (Example: Auto rifles can have high rate of fire but low impact, or low rate of fire and high impact. Etc.)
Armour buffs the Strength, Discipline, and Intellect stats. These determine the cool down time of you melee, grenades, and super.
OK, I hope that's somewhat cleared up.
Weapons, what to keep and what to dismantle.
I don't know what level right now, but let's assume you are under level 40.
Under level 40, go for the highest Attack numbers. If you really don't like your gun, swap it out, it's not that important.
When you are level 40 and higher you should focus on getting Legendary (purple) weapons (armour as well!) here is where LL becomes important. The higher your LL, the more damage you deal. When you get Legendary guns see if they fit your play style and what perks they have (some are better than others)
Say you get an LL 300 auto rifle but you really don't like the perks or just hate AR's in general and at the same time you also have a 280 hand cannon with amazing perks and that fits your play style, you should infuse the AR into your hand cannon. To do this you'll need Legendary Marks ( you get them from dismantling purple stuff, daily missions and some quests) go to the weapon you want to keep, hand cannon in our example, and press triangle on it. You'll see an icon on the left of the upgrade tree that says "infuse" click that button and select the AR. This deletes the AR, but transfers a portion of the LL towards that hand cannon. If you are not sure if you want to keep a weapon or not, but you're running out of space. Put it in the vault (the 3 big pillars in the tower or next to the postmaster in the reef)
Oh, keep high level Blue weapons as well, you can use them to infuse into your purple weapons.
SUNSINGER, The God of year 1!
While Novabomb if o so satisfying, the Sunsinger in invulnerable during Hard Mode Raids year 1 Nightfall and quite a lot of other places.
The super from the Sunsinger mainly reduces the cool down of your grenades and melee, however wen you unlock more perks on it you can also reduce your ally's grenades and melee's. When you unlock the 3rd perk, it does .... I forgot.

BUT, the 4th and final perk of the Sunsingers super allows you to revive yourself whe you die with a full super. PRAISE THE SUN, MotherFuckers!
Now, I hear you thinking "Why would I keep a full super and not use it?"
Well, this is why, Hard Mode Raids do NOT allow team revives, year 1 Nightfall kicked you back to orbit when the whole fireteam was dead (not anymore tho) and last but not least, The Tlaloc. It is a Warlock only Exotic (yellow) Scout Rifle that fires and handles faster when your super energy is full. To get this gun you'll have to do a certain quest.
I hope to have covered most of your questions with this wall of text.
Send me a message on PSN when you are on and playing and I'll see if I can come online!
