Close Beta has finished... so here goes.
There is so much to like about Kingdom Heroes it is hard to know where to start.
The game is a F2P released by Aeria Games other games include Shaiya, Last Chaos, Grand Fantasia (bloody addictive that one) and 12 Sky
It is based in ancient China and the factions are Wei, Shu, and Wu. After a brief tutorial you are asked to choose your faction. In Beta you could have characters across all factions, not to sure this will continue on release.
I guess the closest game mechanic wise that I have played would be Guild Wars.
The four available classes are all fun to play, class depends on the number of soldiers you are able to command.
Warrior: Close Range; 2 Soldiers (Tank)
Fencer: Mellee and Ranged; 4 Soldiers (MDPS & RDPS, can build for either or both)
Tactician: Healing and Buffs; 6 Soldiers (Healer)
Conjurer: Ranged AOE damage; 2 Soldiers (RDPS)
The quests were fairly easy to find and levelling wasn't a problem, although the game had increased levelling due to it being Beta.
I can't say what the high end game is like, but did level all 4 classes into their 20s (120 level cap) and never found it boring. Whenever you needed to raise the level of your soldier, find a nice patch of mobs, set them to Seek and Destroy and go and make a coffee, have dinner or do some housework while your troops auto level and you along with it. Bewarned though there are random spawning bosses that will wipe you out if you are not there to run from them.....
There were a few little bugs, but not as many as I expected, actually probaly a hell of lot less than any MMO I have paid to play over the last few years.
PvP exists, but I never managed to find it

to low a level. And Battlegrounds weren't available during CB. I beleive this will be frantic with the amount of soldiers involved.
I didn't experience any latency issues which can be a problem with F2P when playing from Australia...... need to wait for OB or general release before judging.
The graphics are great and what you would expect from Aeria...... will be playing Open Beta when available.
Hopefully this helps