I looked at it and decided to go conventional. But my reasons were additional noise and complexity.

If the HWH is in a heated space, then it should be fine. If it's not, then heating the water with the built-in heat pump would not be effective in very cold weather.

If you do get a HPHW, I'd do a fair amount of research first. I wanted to get one, but in the end I felt it wasn't worth the extra expense and hassle (e.g. routing condensate, noise), with a higher chance of reliability issues.

Talk about a diversified criminal enterprise! Jeesh.

Interesting you should ask. I saw one lonely lightning bug earlier this week, and was wondering where the others were.