1) 1-49 lvl is one game, 50-60 is other game to much better.
2) The character leveling in Rift is much more varied (quest, invasion, rift, pvp, more exploration). Better graphics, more difference between spec, more character customization, housing, to much better UI, promotes more social play. WoW is better for casual player, better lore, music and modalities pvp. (all is my personal opinion).