(recovered WF user and field tester here) - I could never recommend the Tempest at this point. The rain is horribly inaccurate for most people, the lightning is basically totally made up, even temperature is questionable in summer sun, and they still seem to have obvious quality control issues with lots of failed/returned hardware.
They're very nice people and have a very good set of APIs and support forums, but to me I would definitely shop elsewhere regardless of price....but I'm kinda an old-school 'stuff should just work right out of the box' engineer type.
Your choice likely comes down to your budget and what's most important to you.
My ecowitt stuff is basically for play and to get a bunch of $12 room t+h sensors working, but the T+H sensors seem accurate to me. The 'ol VP2 is the primary gear here. If it ever died I'd just buy another Davis.