The ZE 50mm f/2 Makro-Planar is available at B&H Photo, and should show up very soon as in stock. The ZF.2 Nikon version is already in stock. The ZE (Canon) and ZF (Nikon) versions are optically identical.
The 50/2 Makro-Planar is an incredibly versatile lens. At f/2, it’s fast enough for just about any type of shooting. It’s a 1:2 macro lens. It’s sharp close up and at infinity. Its symmetric optical design all but eliminates color fringing of any kind, bokeh is gorgeous, and it’s great for portraits too. You can’t go wrong with it; if I had to shoot one lens only, I’d likely choose it, 50mm being neither too long nor too wide for general purpose use.
Add in the jewelry-grade build quality, the deeply recessed front element (flare and damage protection), and the ZE 50/2 Makro-Planar emerges as a winner there can be no reason to regret, unless you must have autofocus. And even there, the Canon “green dot” focus assist works very well.