Yes, Doomsday is an awesome port, I highly recommend it. Works very well. And yeah, both Heretic and Hexen are old-time favorites of mine. Been a number of years since I've played them, now... wouldn't mind giving Hexen another go in particular. That was a really kickass game with a lot of crazy stuff going on, especially toward the end. It can be really rich and elaborate for an old shooter.
I'm wondering why the heck I didn't buy these, back in the day -- heh. These games feel like a shooter, but with basically the medieval-fantasy backdrop.
I tried Heretic over Steam. It's cool, for nostalgia -- in that DosBox form, even without the Doomsday enhancements.
But it feels a lot better running it w/ the Doomsday Engine -- namely b/c I like having mouselook. Everything else on top is gravy, such as the graphical stuff.
EDIT:
Que, I'm guessing you probably have Heretic II and Hexen II: Portal of Praevus expansion (which don't come in that Steam pack) -- so, if you have those, how were those, in your opinion?
Which of that entire series do you like the best, if you had to pick?