AQ just opened on Arthas very conveniently on Friday afternoon at 4 PM. The server crashed about 4-5 times before the gong rang and was then extremely lagged for about 1 and half hours following. After that point, while slightly laggy, was extremely enjoyable until the final charge which once again became 20-30 second instants.
I'd say neutral is definitely manageable to obtain, though is significantly easier if you also have the head of the broodlord quest completed and can turn in the carapaces, the supreme flayers around the various crystal formations in silithus drop 100-200 fragments each and are worth 50 rep themselves.
The mobs around the gate go for 250 for the colossal anubisaths while the destroyers are 375. These pretty much require a large raid 30-40 to take down efficiently and are likely to be heavily camped.
The various crystal formations with "supreme" mobs around tanaris have 2 anubisaths worth 100 rep, a liutenant general for 150, and 6-8 flayers worth 50 (+ carapaces as mentioned). These can be quickly cleared and the larger mobs always drop high level greens and occasionally blues. Additionally occasionally the generals are replaced by a named general Nokhor who is white, he's pretty tough but can be kited to guards easily and drops a guaranteed lvl 58-60 BOE epic. Our drops included Alcor's Sunrazor, Hand of Edward the Odd, Cloudkeeper Legplates, Lady Mayes Pendant, and several others. He's also worth 500 rep so be on the lookout for him if you're rep farming.
Approximately every 40 minutes or so a wave of progressively stronger mobs will march towards cenarion hold and the assembled NPC force, claiming tags and letting the NPCs do the dirty work is easy rep/loots. There will be a yell by various NPCs when this occurs.
Finally theres also the colossi for each hive, Regal, Zora, and Ashi. These are extremely large bugs that hit for about 4-5k non-crit and periodically let loose a 4-5k aoe knockback that upon landing will do 100% dmg too. I survived this once as a rogue wearing my duskbat drape with about 150 health left after flying halfway across silithus. My guild managed to take the Hive Ashi colossus down by chain pulling it to Cenarion hold, this is harder than it sounds as the mentioned AOE has about a 100 yd range, if you can see the bug you're gonna go flying. The trick is to set up chain of people to keep him from de-aggroing, hunter traps set in a line with the hunters as far back as possible are extremely helpful for this as are pallies bubble pulling him along. The other option is to chain zerg the colossi as they do not regen health between pulls, this is gonna take several tries likely incurring a very heavy repair bill. The rewards are 2k rep, 2 BOE epics and a quest to either BB, thorium point, or the argent dawn with a husk fragment for a bag of loot with a decent chance of a nice BOE blue (I got a lousy green). Anyone can take the quest within a time period of the colossus being killed, the quest givers are in cenarion hold near the turn in for "The Calling.
Overall it was a pretty damn fun evening.