The BUGBite holster (https://www.bugbiteholsters.com) is a neoprene mesh ankle holster which relies on pressure to secure the gun to the holster and the holster to your leg.
American Rifleman did a short plug for them, and I couldn't find much in the way of reviews on this from good sources, so I decided to give it a try. I measured my calf at about 16" so I ordered the size B per their instructions. This was on the high end of the range for the size, so I expected it to be a bit tighter, which seemed like a good thing based on the reviews I did find complaining that it would stretch out over time.
In the interests of full disclosure, I have only worn the holster for a couple of minutes in my house, so this is by no means an authoritative review. But I think I have seen enough to share the following thoughts.
The holster does what it says it will do. It fits rather high on the leg, such that I would call it more of a calf holster than an ankle holster. As a result it is very secure; it grips the leg tightly, and the inside is covered with little rubber dots. The combination of the zipper and velcro strap ensure it is not going anywhere. While it is possible it could stretch over time, I do not think mine could get to the point where it would slide down my leg.
I tested it with three pistols, a J-frame 642, a Walther PPS Classic, and a P2000sk, as these are the three smallest pistols I own. I used 5.11 Covert Khakis as my test garment; in my experience these fit about as well as loose Duluth jeans. For reference, I also own an Alessi ankle holster, and can conceal a J-frame in that holster with these pants sufficiently for NPE carry. All three guns showed great retention in the BUGBite, such that I would not be afraid to run or bicycle with the holster and lose my gun. Concealment was best with the J-frame. The P2000sk I gave up on immediately after trying it. Because of how high on your leg the holster sits, the gun really rides pretty far off your body, and concealment was just not happening. The PPS was better but still a non-starter for concealment purposes. The J-frame concealed in what I would describe as the bad side of marginal. I am evaluating the holster through the lens of NPE carry, and for that role, the holster fails, but not by a ton. When walking, a bulge can be detected. I blame this on the fact that the holster rides so high on the leg; the calf ends up pushing the gun outwards, whereas a traditional ankle holster takes advantage of the concave part at the bottom of the leg above the ankle.
The draw is objectively awful; not enough of the grip sticks out to really get a hold of, the holster rides way too high on the leg, forcing you to hike your pants up almost to your knee, and the trigger guard will always snag on the holster to some extent. This was especially pronounced with the paddle magazine releases on the German guns. I was willing to accept this, as my risk assessment concludes that the primary threat would be an active shooter with some warning, and I believe the drawstroke is the biggest downside of ankle carry regardless of the holster. But this is a huge consideration for anyone who wants to use this as a primary or even backup holster.
As far as comfort, here I give it a C-. It is very comfortable when standing or sitting, but when walking, each time I push off of my left leg and the calf muscle flexes, there is a minor burst of pain as the gun digs into the calf. It was worst with the J-frame, but still present with the autos. It was not so bad that I wouldn't deal with it if everything else lined up, but it was less comfortable than the Alessi with these guns.
The manufacturer recommends that the gun be no more than 5.5" long and 4" high. I do not own such a gun, but am sharing this in the interests of being fair. I believe that with an LCP or similar gun, all of my issues would probably go away. Concealment would probably be great, and I suspect the comfort issues would be much less pronounced, maybe even unnoticeable. My issue then is that if I'm carrying such a small .380, I believe I could comfortably conceal it in a pocket, eliminating the need to accept the disadvantages of ankle carry.
In conclusion, I think the BUGBite is really good at some things, but almost demands a tiny .380 to work (shockingly, exactly what the manufacturer said). I think it might be a good solution for a woman in a dress, or for anyone who wants to carry a .380 and can't find a way to make pocket carry work. However I can't see that draw stroke being improved with a smaller gun, if anything it would get worse. Plan on at least 2-3 seconds to fish the gun out and acquire a firing grip. For me, I will most likely return it, but it's really a shame as it doesn't feel like a bad product, it just doesn't seem to work for anything I'd use it for.
TL;DR:
The BUGBite ankle holster works great if you carry a LCP-sized gun, otherwise it won't conceal as well as, or be as comfortable as, a traditional ankle holster. If you want to ankle carry a .380 I think it is well worth looking into as it is more stable and should be more comfortable than a traditional ankle holster, with those guns. The draw stroke is moderately worse than even a standard ankle holster.