Doesn't using tape and even Velcro (which is taped to each surface), produce sticky gooey results, or dry up and fail, in the hot confines of a server?

 

Not a problem -- at least not in my experience with Velcro ... can't say whether double-sided tape would be as reliable.    I've been using Velcro for a LOT of years => to mount SSDs in recent years, but also to hold traditional 2.5" drives and other components in place well before that.  I've never had a "dry up and fail" issue ... and I've had a couple systems that have been running 24/7 for nearly a decade like this.

 

I have one of these in my unraid case two hold my cache pool drives, but i'm not impressed with it. It sags due to the weight of two SSDs and plugging power cords into each drive is not easy.

 

The Akasa PCI slot mounting bracket works well and doesn't sag because it's supported by a dummy edge connector that fits into an unused PCI slot (or PCIe, if you're over-endowed with them, though like drive bays, I consider them too valuable a resource!)

I guess this is one upside of my case being old enough/cool enough to have mounting for 3.5 inch drives (it was meant for floppies, I believe). I don't have an ssd in my unraid box (yet), but the ssd for my main pc (in the same model case) fits in there without an issue.