I had no idea that Poser had HDRI.  Interesting ....

I still love Bryce.  And, no, you shouldn't need to purchase a ton of stuff, or even much of anything after you've gotten the program.  I say this because (1) it comes with a large amount of bonus materials already (lots of skies, and textures, and other goodies), and (2) all of the props and stuff that you buy for Poser can be imported and used in Bryce.

And at this price, you really can't beat it.

Could be worse, could be raining.