Ok, so I have a T-700 I just got for about $140 USD. I originally planned to repaint it to make it look more silverish, but am unsure now because I sorta like it the way it is and I wouldn't want to mess it up. It's articulation is marvelous as every joint you could find on a real terminator is there, every piston works (when you move the hands or feet there's even 3 pistons in the arms and legs that move up and down), the eyes light up (excellent display feature, and the batteries seem to be replaceable)... The only bad part about him is no plasma rifle and no shiny paint job. But then again, he's a T-700.
I give him an 8.5/10 (just for the paintjob and pitted surface)
I also got an Aoshima T-800 on eBay a while back before SS was selling them, cost me about $180 USD. He's nice and shiny(well, sort of cuz mine's the BD version with painted on weathering), but articulation leaves a lot to be desired. The hands are interchangeable, which means that they cannot connect to pistons in the arms to be fully accurate, which means the arm pistons don't even move (nor do the ones for the feet, and the feet can only rotate, no ball joint here). Also the fingers are not poseable at all, and they have difficulty holding any weapons but Aoshima's, which are so thin other figures can't hold them right. It comes with a relaxed hand for each arm, and then a trigger finger hand for the right arm. The hands are filled in where they should be hollow between the fingers closer to the arm (not like the Hot Toys endos). Also most of the joints on the body are ratcheted, greatly limiting poseability (every time you move the arm or leg it makes a loud *click* sound and you can't pose it very delicately)... The eyes are just painted red, and the teeth are the same silver as the rest of him (instead of an enamel color). The Aoshima is also lacking some cable-like things around the neck and shoulders.
I give him a 7/10, for terrible poseability, some innacuracies (missing cables, non functioning pistons), and not having light up eyes.
What I think you should do is buy a T-700 for around $140 USD, wait for a new HT T-800 endo, and if it doesn't come, paint the T-700 silver. If one does come, then pay another $140 or so for the new one.
If you buy the T-700 now and a possible future T-800, that'll cost you a grand total of $240. Half the price of a T-800 on eBay. And then you'll have two awesome terminators for the price of... half of one. And if there is no new T-800, you'll have spent only $140 and you could just make due with having a shiny super poesable light-up eyes endo with a slighlty pitted surface after painting it, rather than a shiny super poseable light up eyes endo with a smooth plasticky surface for $500.
As for the plasma rifle and other weapons, you could buy those separately on eBay... or find someone like me who has a Hot Toys Plasma rifle and would be willing to mold and cast it.
If you don't care about poseability, light up eyes, or a few missing cables and all you want is a shiny terminator right now and you just can't wait any longer, get an Aoshima for $200. But make sure you know what you want, because after getting the Aoshima you may be majorly disappointed if you find he just can't pose the right way or the painted eyes just really make it look bad...