Joined in December 2008, played until March 2009 with a Dwarven Champion hitting level 60.
Ended up enjoying it a load with a good kinship (clan). Did all of the Moria end game content except The Watcher. Had at the time, one of the best Legendary Weapons on my server (a 2nd Age Mace with Fervour, AoE Dmg and some other extremely nice high tier trait bonuses back when the only 1st Age Champion weapon was a Dagger
)
A tank, a single target DPSer and an AoE'er.
The Champion is capable of being an extremely powerful class even when not particularly specialising. Can be effective at pulling hate off other team mates (Minstrels especially) and the only reliable monster skill interrupter.
As a Champion, I was able to take on 4 Level 60-61 Orcs in Lothlorien and come out walking without using my long cooldown abilities. I could also take down 1 single Orc as fast as a Hunter though their single target damage is higher Vs. the bigger single targets.
As a tank, my Champion had several experiences as a tank (with Heavy Shield and Glory) in Skumfil left and right side. It was pretty fun and with good use of skills the mobs just stick to you. Your health is high enough to take hard hits from every mob I ever encountered and you always have abilities to make things a little easier on you.
Short and sweet...
Solo - Champion is easy to pick up, get used to and have some simple massacring. Can be a bit bland as all you really do is hit people all day.
Group - A great Champion is quite possibly the best character in the game. I always had immense fun in turning a good party into a great party or making sure a bad party wasn't so bad it sucked. Many of my deaths were caused by selflessly pulling hate off a Minstrel in a terribad group, allowing the Minstrel to get off critical heals and save the group from collapsing.
A bad Champion is okay but not desirable. They can't clobber reliably, they do poor damage and have little concept of the game. These players are probably terrible at other classes too.
All of my info is based upon my last real gameplay which was March 2009. I know Champion's have had a few nerfs along the way from then but I believe they were rather minor.
Eitherway, you cannot go far wrong with playing LoTRO.