It's arrived and I'm very happy.
First I tried it with a Casio-style bracelet. You can't really go wrong with one of those on any chromed Elektronika.
I haven't fully explored all the functions, but it seems quite straightforward. The count-down timer is easy to set up. Setting the time is like any other digital. The full calendar is a nice feature. The very thin pushers have just enough positive action to make the stopwatch easy to operate. The light is no better than a Casio F-91W, but I expected that. The hour chime is an easy single button action to switch on/off, which is handy. I haven't played with the alarm yet, but the instructions seem to be similar to the 77A.
My biggest criticism is that LCD has poorer contrast than a common Casio. In bright light that is no problem, but my old eyes struggle a bit in low light, unless I wear my reading glasses but I can't do that all the time. When my eye deteriorate further to the point of needing glasses all the time, then the problem will go away, I guess. On the up-side, the larger digits of the 55D display (compared to the regular 55) mitigate the problem somewhat.
You will notice that the case is the larger type than the 55, which I think is needed to accomodate the larger display.
I've now swapped the strap for something slightly more substantial yet still thin.
Now I'm looking forward to the prospect of an Elektronika forum project.