Visually there's not a whole lot of difference. Ideally, you want something where the shape of each name is reasonably distinct from all the rest — otherwise folks will just ignore that odd blot before the prompt.

And then, once you've started naming things as $ENV-$TYPE, someone will want to cram in the location, and the OS, and the team which maintains it, and the customer, and and and. Then someone will reduce all of those identifiers into single characters … and you'll be in the situation I mentioned. Clearly clpudb1 is CharlesCorp's first London production database system!