The Marshall
So, the Marshall doesn't get a bunch of stuff for free. Okay. But, he also costs less points to begin with. He also only has WS5. But, gives everyone on the board Ld 10. So, you pass those checks when you get shot at fairly easily and run forwards like Champions!
The Emperor's Champion
Right...He comes with a one-handed Relic Blade and Bolt Pistol (+1 Attack), Grenades, Artificer Armour, an Invulnerable save in Assault (where he should be), but not against ranged attacks (

) and the statline of a Codex Marine Chaplain, with WS6. All for 90 points.
For a few more points he either;
Gives all BTs +1S, -1I in Assault.
Gives all BTs a 6+ Invulnerable Save, and makes them all immune to Pinning. However, all BTs lose all cover saves (like they need it? They should be in Assault).
Makes any psychic power targeted at any BT unit fail on 5+. Or,
Gives all BTs Preferred Enemy
And, although the EC doesn't take up an FO Slot (4 Chaplains, 1 Emperor's Champion

), he still counts towards the 1 HQ minimum needed to make a legal army.
Chaplains:
Right, since BTs are 4th Ed, they have different level Chaplains. You can have the one that's better and cheaper than a Codex Marine Captain. Or the one that's better and cheaper than a Codex Marine Chaplain. Take your pick.
Command Squads:
Due to being a 4th Ed. Command Squad, they have to be attached to an Independent Character. However, you can have up to 10 of them. And, they grant one of Furious Charge, Counter-Attack or Infiltrate to your Character attached to them.
Also, Command Squads can have Chaplains attached to them that take up no FO Slot.
They can also take Land Raider Crusaders as Transports.
Terminators:
Cheap Assault Cannons, and cheaper Cyclone Missile Launchers. Only by 5 points, but, every bit counts. That, and you can take two of even if you don't have 10 models.
Oh, and you can give them Furious Charge or
Tank Hunters.
Assault Terminators:
Furious Charge or Tank Hunters.
Any Terminator Squad can take a LRC Transport. Not just one.
Sword Brethren:
I'd actually give them a pass if it wasn't for the fact that they can take Terminator Honours and
Infiltrate.
I also think this is the only unit in the army that can't take a LRC Transport.
Dreadnoughts:
Cheaper Weapon Options. Cheaper Venerable Dreadnoughts. No Ironclads.
Furious Charge or
Tank Hunter.
Techmarines:
More expensive. But have extra wounds and more attacks. But, a worse save (can be made better for a rather ridiculous amount of points). Techmarines are probably the worst thing in the Codex in comparison to Codex Marines.
Crusader Squads:
Pretty damn good. Can trade their Bolters for Bolt Pistol and Combat Wepaons (and you should, always). Also can have Heavy/Special weapons when the squad is only 5-strong.
Having no Scouts is kind of crap. But, you can put 'Scouts' in your Crusader squads for 10 points, and use them as Ablative Saves for your Power Armour Troops.
Take LRCs as Transports. Enjoy.
50 point Rhinos.
70 point Razorbacks.
Who cares? You're taking Land Raider Crusaders instead.
They have cheap Drop Pods. But, they only take 10/5 models or a Dreadnought. Their Deathwind Launchers have AP6 which will at least kill Orks and Tyranids.
But, Drop Pods only have BS2. But, they also have Machine Spirit and can fire on the turn they land. Pity that the turn they land in is not Turn 1.
Assault Squads:
Cheaper (at least in the beginning) than the Codex Marine counterparts.
Cheap Flamers and Plasma Pistols. That you can take two of even if you don't have 10 models.
The entire squad can take Melta Bombs.
Land Speeders:
Multi-Meltas are more expensive.
Cheaper Assault Cannons.
Ridiculously cheap Typhoon Launchers.
Bikes:
Slightly more expensive.
But, made up for the fact that you can have cheaper Flamers and Plasmaguns.
Meltaguns are the same cost. But, you can have three of them.
Attack Bikes:
More expensive. Even more expensive to give them a Multi-Melta.
Vindicator:
Slightly more expensive. But, can take Machine Spirit. Always fire the Ordnance Weapon.
Predators:
More expensive than Autocannon + Heavy Bolters.
Less expensive than Triple-Lascannons.
Can also take Machine Spirit
Land Raiders:
Same points cost. But, only carries 10/5. Which makes it even worse than the regular one.
Land Raider Crusaders:
Costs the same as a Codex Marine Crusader, if you had taken Extra Armour. Which, in the BT Codex, you are forced to have. However, the Multi-Melta comes free.
Also carries 15/8, which is odd.
Can take an upgrade that makes them immune to the Lance effect. But, not the Melta effect - which is what you really want.