What are you looking for from your army? Do you want them to have a look that you really like? Do you want painting and conversion potential? Do you want an army that is strong or flexible on the table?
"True, true. These are rather dark times. How fortunate for me, then, that cats can see in the dark."
Well warriors of chaos are men too but they're not as ordinary as bretonnia or empire. Bretonnia have a really outdated army and while solid if you use all the units normally it's still really outdated and needs an update. Most people will think codex creep has made them underpowered and it mostly has. If you have weapons that go through armor then bretonnia will take a dirt nap fast esp. if it's a toughness test i bet. It's an army based heavily on cavalry and said group's heavy armor with decent stats and probably good items and weapon upgrades. They have hordes of cheap, expendable and crappy infantry but with some upgrades or banners can hold the line pretty well. I hear the trebuchet helps the army a ton though.
Empire on the other hand are heavily shooty and tie with dwarfs for the best war machines and shooting in the whole game. Both are fairly overpowered and stupid but the empire as an army is just really stupid.
I want you to refrain from getting dark elves, high elves or possibly any elf army as they are overly powerful and stupid. They're not quite as hard to face as they used to be but you have to remember to shoot them a whole lot, use magic and throw hard to kill monsters at their base units. Dark elves supposedly can do wych lists (or however they decided to spell it this time) which are terribly overpowered esp. with altar of khaine supposedly. At least wyches supposedly have no armor so should be really easy to shoot to death. Elf magic and melee is very strong and if you choose wood elves very skirmish and hit and run heavy and really annoying about it. Elf initiative is probably the best in the whole game.
Lizardmen don't seem too bad but the idea of a mostly resistant to all damage slann is kind of a stupid idea. Hopefully it costs a lot of points to make and once in melee can't do very much for most of its spells. They're hard to break and have decent toughness and armor unless you get skinks which are cheap poisoned shooting units that are good vs. monsters i suppose. Cold-blooded is good at keeping your guys from running away but if you lose a combat badly don't expect them to stick around. Lizardmen magic is supposed to be pretty tough and they have decent units. Remember lizardmen have really poor initiative (worse than dwarfs and ogres even) and fail initiative tests about the worst of anything.
I don't know what to think on the new ogre kingdoms esp. since i haven't played them but they have some stupid new heroes or monsters that negate the steadfast rule you can claim against ogres for pretty much every army. Ogres also had their spells go from being remains in play and easily dispellable as well as easy to cast to be fairly easy to cast and last till the next friendly magic phase instead making it harder for people that actually know about the remains in play rule to get rid of said spells. Initiative is poor for ogres and most spells are boosts last i checked. Everything in the ogre army is expensive in points.
I want a fair bit of possibilities to convert. And I'm looking for a very medieval-looking force that allows heraldry in a good manner. The problem is that if I want that it's basically bre., but I don't fancy all those knights. I want to be able to field decent cavalry AND infantry.
The things I know about the (now) 3 main candidates: Bre. has the ability to field a lot of infantry, backed up by heavy cavalry and archers.
Empire has a wide range of somewhat better infantry and some good cavalry to back them up. Plus they have the possibility to take the steamtank and other shooty things. Guessing that they're weaker in the magic than most other forces because of this.
Chaos (men) have solid core-units, both the warriors and marauders is looking good. But they seem to lack ranged support instead.
So, there it is. A medieval force, a lot of decent soldiers and the possibility to use heraldy and convert some. I'm leaning towards bre. at the moment, just because they HAVE the possibility to take infantry that is backed up by archers.
Most ranged units suck and to an extent they do too even with the instant fencing they come with making charges go worse against them. However trebuchets are decent. I think bretonnia need a serious makeover before you get too heavily into them.