There's so much crap spouted about AES50 requirements!
The critical thing is that it's a minimum spec of Cat 5e (so not Cat 5) and shielded.BehringerWiki piece on AES50 cabling requirements
Sadly, too many people don't understand the conventions used to describe CatX cable. But, in this case, we need STP (shielded twisted pair), FTP (foil twisted pair), SFTP (shieded foil twisted pair but definitely not UTP (unshielded twisted pair).
There's also the solid vs stranded question. Typically, solid cable should be used for an install, stranded cable for touring. Not that you can't use them the other way round, but solid cable will typically handle less well than stranded, and will be more fragile.
Specifying Cat5e as a requirement permits higher categories of cabling to be used. So you can use Cat 6 or Cat 7, but you'll be adding cost and getting less flexible cabling. For an install, no harm in using a higher category of cable, and these days it'd be unusual to see an installation lower than Cat 6 everywhere for consistency. But for touring use, Cat5e cable will typically be much more flexible than higher categories.
Ethercons - yes, always good practise to use them - but make sure you get the ones that mate with the connectors on the X32 and stageboxes (NE8MC & NE8MC-1 for Cat 5e, NE8MX6 & NE8MX6-T for Cat 6A), as there are multiple variants and some are designed to mate with Neutrik's "non standard" NE8FDY connectors. There's a whole world of Ethercon detail, which I've poorly simplified above.BehringerWiki piece on EtherconsNeutrik Ethercon catalogue
I'm not surprised the cable Dan mentioned experienced problems. While it's hard to find all the info on the cable, it's solid cored and *appears* to be unshielded.
For what it's worth, I've never had (nor should I expect) problems with VDC's Tourcat Flexible Cat 6A S/FTP stranded cable with Neutrik connectors.