There really is little actual grind in the game if your talking about purely grinding on mobs for xp and levels. If you mix it up doing the different things in game, you can quickly level through the game and there is always abundance of quests. Since they made the game very solo friendly, there are lot of quests for a player to do, more than enough. Do group content and you got even more big xp streams coming in. Most players find themselves over leveld for areas and have no issue moving through the content and not stuck searching for quests. Many areas also have optional bonus series of quests that can lead to a big final xp bonus/reward. Space, PVP, and group stuff all give good xp too. You will always be questing and doing stuff and not really ever needing to actually grind.
The speed of leveling does not dramatically change either though it does slow down, but feels gradual and if you keep your character rested up for the double xp, even better.