Haven't had the chance to thoroughly test my pair of these by themselves yet, but I did recently throw them in the deep end on a full album recording session in a professional studio. They performed just fine as an M/S pair of drum room mics, and a single one on acoustic guitar gave me the rich, earthy sound I was looking for when other mics came out too thin and twangy (C414, M160, U47!) or too dark (Coles 4038) with this guitarist. This was just one specific case, but still! For this price, it's amazing that this mic could do better than those high-end mics in any situation at all! I did also try it on vocals and it was really not right for the job, so it has its limits. I'm looking forward to trying out drum overheads and electric guitar.
Build-quality has a few imperfections. It's not as heavy as you'd expect for such a big microphone (not inherently a bad thing). The screws holding the mic to its frame are loose by default, and not that easy to tighten to a good tension where the mic is still adjustable but will stay in place. The worst part is the in-built XLR cable. It's non-detachable, too short for a lot of use cases, too long to fit in the accompanying duffel bag, has a cheap-feeling XLR connector, and is attached in such a way that it prevents you from swivelling the mic in one direction on its frame. A simple XLR output on the side of the mic would have been way more practical in most cases.
Can't comment on longevity yet, as I've only owned these mics a couple of weeks.