Hurt Me Plenty. And sure, you'll say I should have done my first playthrough on Ultra-Violence from the getgo. But Hurt Me Plenty is the standard.
It's not like game mechanics change between Hurt Me Plenty & Ultra-Violence. If you can hop around on one while barely taking a scratch, then you can do the same on the other.
All enemies did at time is chip a bit of armor away. And I nearly always saved my ubers (quad, invuln, speed, berserk) thinking a larger wave of enemies would come which would require a well timed uber to beat.
I only used the BFG on the final boss. Hell, at one point I caught myself thinking, "what's the green spinning thing on the ground that I can never pick up? Oh, right... BFG ammo".
Same thing with the chainsaw. It feels like such a cop out weapon that I never used it. I'm sure that on Ultra-Violence/Nightmare/Ultra-Nightmare it's a requirement to use.
Either way, it's a beautiful game, with some nice weapons, but overall I'm not convinced it'll live past a single playthrough for most people. The choice to focus on achievements and trials feels wrong to me. The fact secrets on the map now grant permanent upgrades in the form of argent energy is also something that doesn't sit well with me. I was fine with the old style secrets which gave you weapons slightly earlier, health/armor/ammo or a uber.