I'll throw in my two cents...
I just bought a Vapcap M, mostly due to the hype (particularly on the Vaporents Sub at Reddit). I figured for $50, even if the hype was only half real it's worth taking a chance.
When I got it, my biggest surprise was the draw resistance with the carb closed. If I'd known what the draw resistance was going to be like, I probably wouldn't have bought it. That said, I'm not going to give up on it. I'm still very much in the learning phase, but working on mouth pulls, partially closed carb and carb feathering to get the benefits without the frustration. And I'm definitely making progress each time I use it. But yeah, carb closed is like golf ball through a coffee stirrer; carb open is virtually no resistance, but how much vapor can you really get like this?
When I first got it, the torch I was using was a single-flame Ronson JetLite. These lighters have surprisingly good reviews on cigar forums, and with the Ebay bucks I had, I got mine for less than $3 shipped and pre-filled. The lighter itself seems OK, but with one smallish flame, it takes a good 15 seconds or so to get the Vapcap to click. I found my VC results with this lighter to be consistent with a lot of what I was reading: first heating session has tasty but fairly weak vapor; second session is where it's at; third is decent; forth and beyond is diminishing returns and not-too-great of flavor.
As a sufferer of first-world problems where I deemed 15 seconds too long to wait on the click, I ordered a JetLine New York triple torch lighter. I used it with the M for the first time last night. Night and day difference! First off, the click comes in a single-digit number of seconds now. And my first heat cycle session was the crazy one; second was pretty similar to the first; and my third didn't have much left; and after that it seemed pretty well spent. I'm certain I did not combust, but my ABV was coffee-ground dark, quite a bit darker than anything I've produced with the M or my daily driver Underdog.
So, even though I'm still in the learning phase, and still making improvements to my technique, I'm happy with the product. I don't see it becoming my daily driver any time soon; I'm pretty sure I'll stick with log vapes for the long run. However, it does meet my overall expectations for what I wanted when I decided to purchase it: something that is truly on demand. Log vapes can be on-demand if you leave them plugged in all the time. But I don't vape every day (and have little ones running around) so only plug in my Underdog when I want to use it. It takes a good 15-20 minutes to get to an "equilibrium" heat state. Normally not a problem for me. But every so often I decide I want to vape later in the night when I don't have 15 minutes to wait on the dog to heat up (more first world problems, right?). Also, the Vapcap makes for a nice alternative "new toy" to play with to change things up from time to time.
I will say: though I'm sure my Vapcap technique is far from great (at this point), it's definitely at a serviceable state. And the fact that I can get the effects I want with two or three heat cycles from one load---to me that speaks to the VC's vapor quality and efficiency. I don't believe it's as efficient as a log vape, but it's on par with the Arizer Air's efficiency.
Several months ago when I transitioned from the Arizer Air to log vapes, I realized I'm not really into session vapes (such as the Air). I like the "one-two punch knockout" style of log vapes or now the Vapcap. At least when it comes to vaping, I prefer "shots" to "beers".
And that's what really impresses me about the Vapcap, and where I suspect some of the hype comes from. For $50, I have something small, simple, and rugged, and I do think it delivers well beyond its price.
So my TL;DR is this: I don't think it's a top-tier vape; however, for the price and size, the vapor quality is amazing. Silver-medal vapor at a runner-up price.
I'm curious if the titanium Omni models are worth the 3x (or more) increase in price? I've seen several people say yes---supposedly much better carb-closed airflow, and the ability to lock-in the carb at the sweet spot. Despite my overall positive take on the VC, I'm not sure I'm (yet) willing to spend $150 to find out.
Lastly: though I haven't taken advantage of this feature, I like that I can use any heat source with the VC. Many years ago I was an avid camper, and I'm hoping to get back into that hobby soon. While I could get a big old battery pack for my UD, I can confidently say I don't want to deal with the bulk and weight. I think the VC absolutely dominates for someone concerned about size and weight issues for camping and hiking. Save butane and use a burning stick from the campfire to heat the VC, with the click taking out the guesswork.