Heroic mechanar - stuff I wish I'd known
Just a few short tips in case someone should be in a situation similar to mine (farming the crap out of heroic mechanar for a sun-eater for 3.0).
1) Tinkerers are evil and annoying and must die. I had the hardest time on these, especially that pull right before capacitusl, until I figured out that their bombs have a delay timer, meaning that you can pull them with your tank, and focus fire them down while your tank runs around consecrating like a headless chicken. If you don't stay still you'll take minimum damage from the bombs.
2) Destroyers are annoying and I'm chainhealing through these, but you can stun-interrupt the charging-fists effect, which helps a bit.
3) Gauntlet is annoying too. Two waves consisting of each a bunch of mobs, a destroyer and another bunch of mobs. Be sure to be full mana/buffs etc before you pull the first wave. Conserve mana. Cast mana tide and use potion on your healer (assuming resto) around 40-50% mana. This is assuming you don't outgear the instance obviously. The second you kill the last mob of each bundle, drink/eat. If you need to, you can keep the last mob of the first bunch alive for a bit while you regen some mana, since the destroyer wont come until the last mob is dead.
4) When you clear the gauntlet event you dont have a lot of time before the boss is on your ass - he'll come charging about 30 seconds after you kill the last wave. If you tank him far enough from the group you can simply get you dps up and burn him down since add won't get to the group and afaik they spawn based on time not his health percentage, so heroism+trinket+healer dps = win.
This was my first heroic instance and I was actually surprised at how easy it was, probably due to the fact that I had wiped about 20 times on the 3rd boss of mgt normal before coming here.