I have an Optoma HD3300 and was thinking of changing it out for the HD131xe given it looks like an upgrade, though the HD3300 was a stepped-up model of the past. Anyway, I saw lots of threads about glasses, so first thing was to try all my 6 glasses--two of which are Optoma's. They work great on the HD3300, but not one worked on the HD131xe at 1080p 24hz until I went into my Sony bluray player and activated Hulu and 720p at 60hz, then they all worked. So, it appears that 144hz glasses ARE required for full 1.4 3D.
That said, what I saw was not as good as my HD3300, especially 2D TV. Looks great on my HD3300 and awful (to me--you might not notice) on the HD131xe, and I tweaked it as good as I could. Bluray is about the same. I was amazed that the HD3300 had better contrast and pop, though that's probably because the HD3300 has better noise circuits. And, speaking of noise--yikes, the HD131 is noisy with lots of block and mosquito noise--again, especially with TV input (1080i 60hz). And brightness--about the same. As for sharpness, the HD131 has a soft-noisiness to it that's hard to describe. It looks sharp, but when a person's face is up close, you do not see the pores and wrinkles (fine detail) as you do with the HD3300 even at max sharpness, yet text and fine lines look okay. All in all, I'm going to send the HD131xe back, as it's probably a good step up from a cheaper 720p 3D projector, but has a ways to go to match the projectors with more built-in controls. The HD131 also weighs a couple pounds less and is smaller than the HD3300, but has the same projection footprint. I would think that if you watch a lot of TV, and you already have a good projector like the HD33 or HD3300, there's no need to chase the bus, plus you won't have to buy all new DLP-link glasses. For someone just starting out, I doubt if you'd notice the soft image noise and it's a good first projector. For someone who has had a taste of fine projector wine, you might regret it.
I also heard from an Optoma rep that the HD131xe is selling very well, but the first couple of batches are getting returned for replacement with component issues, so take that for what it's worth. It might be why Amazon is dumping them right now.