Brotherhood Champion

THere are a few HQ choices that appear VERY infrequently in GK lists.
The most obvious is Captain Stern (WHY would ANYONE take him??), Inquisitor Valeria, Inquisitor Kamarazov.
.
But the one who's most intriguing is the Brotherhood Champion In My Opinion.

The First problem I guess is how to use him?

Do you go fluffy and attach him to a Brother Captain and a unit of terminators. This means you lose Deep Strike......and the Bro Captain doesn't really NEED a bodyguard.

Put him with a unit of purifiers? That's nasty, but it's 100 points on a unit that doesn't really benefit from the Champion's abilities I think.

Same problem with Terminators. if you put him in a land raider with a unit of terminators it's an expensive target....and if you put him with Strike Squad they're not the best in CC.

So what does that leave one with tactics wise? Put him in a stormraven and have him on the battlefield on his ownsome? Expensive, and wasteful as one good lascannon shot and he's toast.

Maybe put him with a group of crusaders and deathcult assassins in a stormraven or land raider.........any challenges come their way and the Champion can usually take on most comers (in fact he's one of the few that has a chance against UBER KILLERS like Abaddon and Hesperex in CC).

how would you use him?

The problem with the Champ is he has two possible roles and he's not very good at either.
Role number 1 is as a combat character. However AP3 and his low number of attacks vs regular characters limit him badly, and most ICs are going to be rocking a 2+ save these days. Sure he can try and tie someone up by shielding, but that's not always worth it unless your opponent has a monster character, and if they do they'll feed you a sergeant or something instead.
Role number 2 is as a support character using his rerolls to hit on the charge to buff a squad. Unfortunately he's pretty much completely outclassed here by the favoured Inquisitor build of psyker TDA/psycannon/NDH. For only 10pts more you get an extra relentless psycannon(with precision shot no less) and far superior re-reolling.
Personally I think the BroChamp should join the likes of the other characters you mentioned, which is a shame because I really like the fluff, and it's an awesome model to kitbash (since the official one is blegh IMO) here's to hoping the next dex makes him into something much more usable.

Keep him around for fluffy games or campaigns.

He's just too expensive for how fragile he is, imo.

In a 2000+ game would you consider putting him in a Paladin squad?

I personally think he's best used in small points games. Where it'll cost prohibitive for your opponent's characters to be rocking the 2+ armor save. But even then generic Inquisitors tend to be cheaper and do more. Especially with their Divination powers. But if you want a cheap all Grey Knight strike force then he's the guy.

hes one of my favorites. i put him alongside my paladins or any other main strike force i own. move forward. split him off the unit and attack the next most dangerous target the opponent has to offer. while the paladins take care of the rest of the force.

standing with defensive stance, a 2+ and a 3++ that both are rerollable is incredible as tarpit. especially as there is no more null zone or a guaranteed way to get misfortune in divination.

my brotherhood champion held off draigo + 10 paladins for 3 full rounds. 2 greater daemons that where in combat with a other unit. 10 meganobz with waaaghboss. and even multiple times a unit of hammernators with lysander/calgar or a chapter master/libby.
most of the time i tarpit units that are 400+ points. for rounds. thats time my main force can fight against a crippled foe for a simple 100 pts spend. great.

all thanks to the rerollable 2+/3++. while the rest of my army swept clear the enemys objectives as his hard hitters are tarpitted for rounds after rounds. not able to counter my heavy units efectively.
its especially great now thanks to challenges. if a enemy decides to accept its his greatist mistake. his odds of running out of combat then are almost 0.

Like I said, in challenges he rocks cause his ability to reroll saves is awesome and he's one of the only models that has a chance against the greatest CC character out there. Abaddon. (the others being a daemon prince with the black mace and necron lord with mindshackle scarabs and warsythe).

One use I can think for him (the way I would play him since I like Overwhelming Firepower compared to all out assault) is him with a techmarine and a group of Crusaders and Deathcult asassins with a Banisher in a stormraven.

Able to tarpit an enemy unit. Banisher (if my memory serves me correctly) is a Zealot in 6th, so that means unit gains Hatred and Fearless.
That's nasty IMO