So mine finally came last Friday. 12/12/13 backer with a Gray Ti & a SS... serial #s for both around 1200. My impressions are pretty consistent with what everyone else has said, but here are a few impressions anyway:
1) My first impression out of the box was the GH was smaller and lighter than I expected. I was ready for it to be a little bigger than a typical pen when in fact its exactly the size and heft of a typical nice pen. The Ti is very light...so much that I was worried that it would be flimsy at first. I have a W9 Tech "8" and that thing feels substantial and super rock solid in the hand. Upon further reflection though both GHs seem solid and well made though.
2) For those torn between the SS and Ti models who are wondering whether the Ti upgrade is "worth it", I have to say the differences between the units are very minor. I actually like the look of the SS better, in part because the pen clip on all models is made of SS so its a better visual match. The extra heft of the SS feels good in the hand (its still quite light), and I don't think the performance/heat differences are that noticeable. So if you're torn on which to get, I say get the SS and you wont be missing out on much.
3) Performance is great so far. This thing feels very powerful for a portable, and when you consider that its one of the smallest vapes out there you will appreciate how much HL has pushed the envelope of whats physically possible with the design. Vapor temp is warm and the unit does get warm, but no so much that I've felt the need to take the silicone thingie out of its wrapper. Its totally usable without it provided you use as intended...i.e clicking it off after a few hits and letting it recover for a sec before passing it to the next guy. But the flip side of it getting warm is that its nearly impossible to pull harder than the heater can manage. So I've been taking big rips with it which leads to fewer hits and less "sipping" to get the job done, and doing so probably keeps the unit much cooler than if I were taking slower pulls. I never take such huge rips with my Mighty for example...I don't think it keeps up as well... but with the GH it seems like it was designed to be used that way.
4) OK... I admit I may not be impartial after being a backer for 2+ years, so instead of hyping this thing up let me tell you what a few friends have said after trying it. These are the guys who have rolled their eyes every time I've said that the GH is coming and teased me mercilessly when it didnt (as only good friends can do). Net-net, they think its great and are ready to pre-order, even with all my warnings about slower-than-promised delivery times and potential reliability issues. There's one friend who hasn't tried it yet who tends to be sensitive to warmer vapes, so it has yet to be seen whether this will be a fit for him.
Anyway, so far so good with the Grasshoppers. Overall, I am truly impressed.