There are two realms (light and dark side) in Shaiya that can PvP in certain areas one against the other. Each realm has two races and 6 classes to choose from tank, warrior, archer, thief, mage, healer archetypes. The skills available to classes on both sides are the same just minor differences in stats and looks. Graphics are quite good for a f2p game (shaiya gold), quite bobastic and nice effects when skills and spells are used.
The system requirements are decent and while on low end computers the graphics are not that flashy, game works fine on low settings. Comunity is decent, quite frequently ppl help each other in game, and Game Sages are very active. Virtually no botting which is quite different then L2 experience. Grinding is at a decent pace so you can actually enjoy PvP in all brackets, but may feel a bit too much for a WoW player.
You can also stick until high level (shaiya money) only to PvE maps. Doing early PvP will increase your stats slightly and is quite fun 2 although this is your choice. Items and experience drop in PvP so be aware. You also get xp by killing those pesky enemies it's up to you.