How Uncomfortable Are Hardtail Bikes?

A hard tail is extremely uncomfortable and you'll also have your suspension entirely in your front end so they handle quite differently.

I've only  had 14 motorcycles over a twenty year period so take it for what it's worth.
Hardtails look great and nowadays you can get the same look from softails as many manufacturers produce this look your after without sacrificing your spine or worse, losing control.

But if your anything like I was no one will talk you out of it you'll just have to learn on your own.

Best of luck to you and remember to keep the shiny side up,
SteveE

If you have any back problems this kind of bike is not for you. There are bikes that have the look without the discomfort. The hardtail is a 50/50 bike. 50 miles 50mph then park it.