The DFRPG has a fair number of small rules clarifications, modifications to simplify, and changes that make for a potentially better GURPS experience.
Berserk now specifically mentions Change Position as your required maneuver when knocked down; I run it that way myself now.
Signature Gear is now a 1-point advantage tacked on to a specific item. It is no longer 1 point per $500 of value (round up). Nor does it give you any money. It's just plot protection for an item. I like that a lot. It's not new top GURPS in the DFRPG, but it's new to the DF line and DFRPG sub-line.
Slam is a Move-modified ST-based attack. No longer do you need to calculate Speed & HP to get a number, but just use your listed damage.
It's clear when to use Speed to give an attacker a penalty to hit in combat. It's not often (AOD (Increased Dodge) and Move, pretty much) but it's clear when to use it.
Relative positive SM isn't a penalty for attacking; not that I ran it that way (it's hard enough being an SM+4 giant without taking a -4 to hit a human and a -5 or -6 to attack a small halfling). It's still a bonus for grappling. You get hosed on being hit, but you grapple better and don't have worse striking.
Overrun and Trample attacks are clearly spelled out, and who can use them is also clear. Yes, big monsters can just walk through you and get a free slam or whirl in a circle and tail-slam everyone. Don't stay too close to the Rancor.
Crippling Injuries get a handy table for typical delver-level HP.
Combat at Different Levels is simplified, and it's abundantly clear what the effects are. Fighting flying monsters sucks - +2 and -2 to defend, and if you're not the one flying you're not the one getting the plus.
Knockback damage - from being knocked into things - is listed. Ah, just like Champions.
Unliving, Homogeneous, and Diffuse Target damage is in a nice a nicer, easier format.
Weapons use the GURPS Low-Tech damage listings and added weapons. Since I'm the one that did those, I'm very pleased to see this made core for the DFRPG.
Group Skill Use is clearly spelled out.
So is Surprise, and how to use it in a dungeon.
Everything is figured. Well, more or less - you don't need to modify costs for power sources or limitations, add enhancements for special bonuses, etc. It's just as-written, no modifiers. So Turning, Healing, modified Wild Talents for spellcasters, etc. are just as-is traits to take. Less figuring = faster chargen.
There is more, of course, but those are some highlights I found that might show you why we're swapping Basic Set for Exploits for our long-running DF game.