Robert: I wouldn’t rely on Adventure Alan. OR Helium doesn’t exactly get rave reviews from people who own them. It’s main strength is being light and packable, but it isn’t known for being reliably waterproof. Nor is it tops at breathability. So kind of mediocre performance in general.
Montbell Versalite looks like a far superior jacket in that category. Or watch Rab for a new version of their Phantom when it comes out this Spring (presumably soon).
But if you want reliably waterproof and as-breathable-as-you’re-gonna-get, then ShakeDry and Outdry are really the only games in town, as you pointed out in your OP. (Or Frogg Toggs Ultralight, which is a budget version of the ShakeDry/Outdry concept. Probably not as breathable as either of them, but I have never seen a test report for it.)
Stephen Seeber tested the recent Columbia Outdry Extreme Mesh at 2720 MVTR, which is slightly better than EE Visp or ZPacks Vertice and it’s Outdry so not prone to wet-out like virtually all other WPBs.
If you want a jacket, that appears to be a top contender.
As Mark Verber pointed out, Montbell’s Japanese site still lists the Peak Dry Shell, which has the top-measured MVTR of any of Seeber’s rain jacket tests (see Table 2). I have never seen a negative report on that jacket.
If you wear a pack, then I wouldn’t get too distracted by pit zips (or lack of them). They work best without a pack.
The jacket-vs-poncho debate appears to come down to expected conditions. For dry climates, WPBs with face fabrics may perform well enough that people buy them. Many of us in more humid climates have never seen them work as advertised. I have seen reports that GoreTex works great in Antarctica and Afghanistan.
Either way, though, having an outer face fabric is, at best, a maintenance issue. If you want bulletproof water resistance, then it’s either ShakeDry/Outdry/Frogg Toggs UL or permanently waterproof.
Timmermade makes waterproof jackets in silpoly and Dyneema. His Mega-Zip Pullover has a unique zipper arrangement for side ventilation under a pack. I mentioned LightheartGear and AntiGravity Gear previously.
That is pretty much the current state-of-the-market report that you requested. Spring season is coming, so there will be new models soon. Other than the new-ish Columbia Outdry Extreme Mesh, I haven’t seen any rumors of any better technology in the works. On the contrary, it appears that ShakeDry is expected to fade away. Perhaps it will be replaced eventually, and that is something to look forward to. But, as I write this, that is still just one possible future.