I hate d20. I hate 3rd Edition. I hate adaptations. I hate, I hate, I hate.
I love Green Ronin's d20 Black Company RPG adaptation. I love it with all my heart. I played it for an extended period with Frank and Jason (Keir and Cain respectively, in the Hounds) and we all enjoyed it thoroughly. There's just something about Green Ronin's products that I can't help myself but love. Their d20 Medieval book (complete with rules for disputation and "social" combat wherein scholars send letters to each other and refute philosophical treatises) is also just fucking great.
Writing rules to resemble a book is hard as hell. I threw out their Black Company setting stuff because I always have to design my own settings. So instead we played in a pseudo-Black Company world that included lots of things that "felt" like the Black Company but weren't actually. The Company of the Crow was our stand-in and Nah'Khud, the infamous mercenary leader who had etched on his breastplate "Enemy of God, Mercy, and Mankind" the Captain. Sergeants like Dealer, Hammer, and Sand led the platoons and the desperate, nearly destroyed, betrayed, and ruined Company battled its way out of the Valley of Drown (after the disastrous engagement at The Saw, a series of narrow canyons near the edge of the Red Lands) and towards the ancient city of Torch.
This gave us a chance to use the platoon fighting rules. Frank played Diver, a mercenary picked up in the ruinous land of Drown, while Jason played one of the sergeants: a veteran archer named Twitch. Together they led one of the platoons breaking out of the Valley of Drown (by fighting the notorious knights Crouch and Tyle). The medium scale combat rules (the game has skirmish, platoon-scale, and full battle scale rules) worked smoothly and with little calculation. They reminded me, in fact, very much of the Birthright skirmishing rules.
Once that was done and the Company's rag-tag remnants safe in Torch (where they signed up with the councilar family of the Sabines, serving Sabius Lutrius) most of the gameplay devolved to street level encounters with rag-tag elements of the Qualaeine conspiracy. We got a chance to test the magic system (the Company wizard, Smoke, traveled with Twitch and Diver on several occasions—this was before I'd read the Books of the South and met the ACTUAL Smoke of the Black Company novels) and it worked... beautifully.
The permanent crippling affects caused by CON damage, the maximum hp cap, and the CON damage on surprise rounds worked together to create real memorable play as well as that feeling of gritty down-to-earth combat. Sand, a huge Obsidian Lander, was crippled forever in an ambush by the Qualaeines; his knee was sliced from behind and his movement rate permanently reduced by a hitch-step limp. This is the kind of stuff that games need. Desperately. Less glowing swords and super-high-jumps and ten-thousand-arrows and more of this low to the ground fighting. This is the where the magic happens.