So...while I like the HDRI stuff and while I do believe that the base image quality put out by 6 is superior to it predecessors I can't say I am all that impressed.

For grins tonight I tried opening 6, creating a default random terrain, assigning Flat Grey texture to the terrain and the default plane and rendering.
3 minute render time.

I opened 5, the corel version since 6 installed over top of 5.5 for me automatically, did the same thing.
sub 30 second render time.

I'm thinking I could make up the image quality difference in post work.

Terrain brushes? Not seeing any advantage there since I could have done that with photoshop anyway...(I would have given them FULL props on terrain brushes had they included a nice set of splash ripples that didn't include a "barrier")

and as cool as the HDRI stuff is it created wierd artifacts in the first image I tried using it on...the halloween door...so I did it without in 1/10th of the time. (Of course that may have been caused by the particular light probe I chose so not a full rejection of it yet.)...and it still adds a ton of render time.

Am I missing something? It's cool...but I was really hoping for another performance leap which I am not seeing. Someone educate me please? I am willing to be converted to being a believer...