Let me sum up my [many] experiences that have been accumulated ever since this game in different servers
Do note though that my review doesn't include external factors such as sets. I based the following from my observations on them as [characters] and some in-game default stat-modifier items, i.e. wings, pets for dark lord.
BK
pros
-Outrageous HP
-Fairly high defense
-Does high damage
-COMBO
cons
-Melee fighter
ELF
pros
-range
-ice arrow
-buffs
cons
-Demoralizing low health
-low damage (PVP even with her buffs)
WIZ
pros
-hard to kill when paired with teleport skill
-annoying when used with lightning skill
-range
-MS buff (def increase)
-average damage (PVP i.e. ice storm skill, nova)
cons
-outrageously low defense (even with MS)
-very easy to kill when caught (could not teleport fast enough)
DL
pros
-High defense (with dark horse)
-Fairly high damage (even in PVP)
-Moves fast (with dark horse)
-Critical damage buff
-range
-Lvls fast (with dark raven)
cons
-average hp
MG
pros
-None!
cons
-probably the weakest char in game
SUMM
pros
-Insane damage bursts... consecutive LAGUNA BLADEs anyone? (PVP)
-buffs (reflect)
-range
cons
-low defense
-low hp
RAGE
pros
-deals consecutive bursts of damage, faster than SUMM
-high HP (buff)
-ignore buff
-dsr buff
cons
-melee
-average defense despite being a melee char (attributable for being without separate gloves in his sets)
Disclaimer: I hold no liability or whatsoever that may arise from reading this post. This is just my personal opinion, and yes, this is FREE.