Well, I went through the same quandry as the OP and tried out the Moment (thanks to Henry) while awaiting my Sublite 2010. I own the Sublite and it's been a decent kit for a shelter and while I didn't experience a whole lot of rain over the year that I've owned it, I thought I would add my perspective for your consideration. The Tarptent is a great tent in it's simplicity. As stated, I tried out the Moment and it's so easy to setup. My Sublite is pretty comparable to the Moment and I would give the nod to the Moment for ease of setup. It's almost freestanding in relation to the Hexamid, and obviously takes much less time to setup.
That said, I have experienced condensation issues with the Tarptent which may be more about the location of where I setup than the design or fabric. I also like you researched these forums for feedback which is why I went with it. Recently I've gone ahead and purchased the Zpack's in terms of cutting weight from my tent weight. I have to say the Zpacks is featherweight in relation to the Tarptent. Yes, there's more staking, but what is a couple of minutes more for setup compared to the amount of granola weight add on? Well, as you start getting more into this, you find that it's like the law of diminishing returns- by $$$$. I think it's worth it in the long run to spend the extra money on the weight savings depending on the amount of use that you get out of it. But , as some have argued, the silnylon has been around a long time and has proven it's mettle as a durable material. I would give them that, but for a tent covering I went with the application. Since it's a cover, I don't see the relative merits for durability being superior with silnylon over cuben. If it was a pack, then yes. One thing that others have failed (from what I can see in this thread) to mention though is the ease fo getting into the tent. This may not be an issue for you depending on your flexibility or size, but for me, getting into a Hexamid with the vestibule that I have is somewhat of a pain. I'll qualify that though. I'm 5-9, 185 and not the most flexible guy at my age. I only took out my tent for the first time this past week on the High Sierra Trail, and found that the ventilation was exceptional (almost too good) and experienced rain, wind, and all kinds of inclement weather that the local thunderstorms produced. Given more experience with the tent, I would of liked to of been able to keep the sides down to prevent the amount of sand that the storm blew in. None the less I'm not sorry I purchased either one. I have to tell you though the customer service of Zpack was much better then expected with everything I have experienced to date. I haven't had to test it yet (as I have with the Tarptent) but Joe's attention to 'getting her done' has been great! In summary, Tarptent has the advantage in price, ease of getting in, and set-up, while Zpacks has it in weight and (to me) ventilation. Again, I don't have years of experience with backpacking but as an end user who doesn't set a price on my recreation for the most part, I would weigh out your criteria and possibly get a hold of both and try them out. It would really make your decision process that much easier. Perhaps either manufacture has some way to test them out prior to owning.