Tried a pair of 8x42 HDX's yesterday against my own 8x42 HD's.Seems the Zeiss people carefully designed the HDX to produce maximum entertainment on this forum.
Looks like it's not being much of a success in other ways.
Seriously, though, the OP in the first post does sum it up by that word success, and NDHunter/Jerry nicely in post #35 above with a few words more.
Seems Zeiss's new models in recent years have impressed us so much that that we expect something mystical when they add a letter X to an existing model!
Both are lovely bino's but whilst I could not tell any difference twixt the two optically, the eyecups were a 'better fit' on the HDX. However I do have the longer eyecups on my 8x42's and they are fine.
I won't bother to fork out an extra £300.