is one of the best sites, and they were the original site Dark Horse referred all their direct orders to (from conventions, etc). They are quick to ship, and well priced.
As far as ordering, I wouldn't take my chances. Order one from a trusted site (like TFAW) as soon as it is available to order (which it is not, by the way). Some go quick and are never seen on the primary market again. A Stormtrooper is destined to be incredibly popular too, and people will surely by multiples (I will probably buy a case of 6).
Good luck if you decide to go back and collect the others as well. The OT busts wont be too impossible, Vader and Fett are still pretty darn difficult though. The Prequel era stuff is still pretty hot. I sold my entire PT collection (everything except the Clone Pilot) for $1000, and I had tons of replies of interest. Buying them individually, expect to pay about $1200 for all of the PT busts, a few hundred more for the Pilot and silver Jango busts.