ok
mass scouts
arbiters are most likely THE best air unit, only if u have like 4 of them
Arbiters+reavers/dragoons/zlots/templars=complete mass destruction.
The arbiters recall the reavers or goons, or lots, or temps, then let everyone else bask in the complete destrucion.
Arbiters can freeze a whole army, then recall a whole army, right into an enemy base.
BC's? forget it. Scouts and arbiters OWN bc's(tried, tested and true). Carriers? completely defenceless w/o their intercepters. I think that they should get the nickname "noobie mass unit". But, if u are good, and have like 6 carriers(all ready, full intercepters), 3 scouts, 2 corsairs and 1 arbiter, you are going to get raped by the finger of god. BC's alone are not so good, and to get the yamoto gun, they have to wait a while (150 I believe). Guardians/devourers are ok, but devourers get owned when its even fighting(1v1, 2v2,3v3,4v4,5v5) Guards are ok, good range, but slow as funik. Mutas = weak mothers, and I ain't even gonna TALK about them. Wraiths, they are pretty good when you have a whole slew of them, and you cloak them all. Sci vessels, can actually be one of the funniest crafts in starcraft, you can do things beyond belief with that, irridate 1 hydra in a hydra army and POOF theres like 8 hydras down. Corsairs are AMAZING, get disruption web, disrupt some air defences(spore/turret/cannon) and send your arbiters in for the mega kill!