PVP is fun in SWTOR however you will notice some very big balancing issues. Classes like Jedi Knights/Sith Warrior and Vangaurd/PT's are very OP and as such have saturated the pvp scene. It is also very much like WoW's battlegrounds and there is almost no open world pvp. There was a planet dedicated to this but due to lag and poor design (leading to exploiting) the pvp mechanics were taken out.
There is also very little difference between PVE and PVP servers. I leveled on two PVP servers and through the whole process I saw reds half a dozen times due to factions having their own questing areas.