If everyone relied exclusively on reading old threads on used topics, there would be no new threads, and ScubaBoard would be forced to shut down.
I bought a PLB several years ago, after reading the then current threads. I had no trouble finding a suitable PLB. What I had trouble with was finding a suitable canister for it. The one I finally got turned out to be much bigger and bulkier than I needed. Moreover, it came in a holder designed to mount it on a belt. What a laugh! That thing fell apart in no time.
i have not looked into the issue since then. The problem with diving with PLBs is that the PLBs themselves are not designed for diving--you can't take them to any reasonable diving depth. That means you have to find some kind of container to hold them, a container designed for something else. It would be great if someone were to create one that was designed to fit any of a number of PLBs--most are about the same size.