Celtic Heroes

Before update to answer your question i would have to ask myself which class can lvl the best soloing, since there was no point in grouping with other players (there was no xp bonus).
But now lvling with out a group is just wasting good time and elixirs.

the class easiest to lvl from lvl 60 to 150 is a druid in my opinion.
the reason is because of it's high demand in groups and later on in wyverin groups in which you kill in a fast pace and get 17k+ xp per kill.
if you are playing a rogue, ranger or a warrior then you wont be able to get into one of those groups untill you hit 135+. requirment for a lure monkey will probaly be lower.

So since now Celtic Heroes is a group game, the class you must have in every good group is the class you want to be.

and that class is a DRUID.

Rangers hands down.

With my Ranger (this is going back to blue eye times), I could get 1 level per elix on ranger between 90-100, with my Rogue I could only get just over half a bar per elix with a fair few Resto pots wasted. (Please note that the Terrifying Gaze skill is cancelled out by the effect of Rapid Shot, so Rangers get to bypass that horrible skill!)

So unless you wanna use a crazy amount of pots, I'd go Ranger. I personally think (resto) pot levelling is a massive waste.

lol for this u get super hastes or something but rangers are the easiest tho they take time with different builds. i would say rangers are the easiest to lvl and solo but good groups are good too.

based on my own experience with rogue, ranger, mage and warrior, and what I see of high level druids in my clan, every class is easy to level and can level fast if you use lots of lix and pot and dual device. I levelled my mage to 135 in two weeks. I gave up on my warrior at 126 because it is such a boring class. My ranger is at 137 but I slowed down because I find the class too slow moving. My rogue is struggling at 159 as it doesnt make sense to use lix at this level. In all cases, I solo levelled mostly or entirely.

I haven't tried a ranger but on my opinion easiest is a ranger

Rangers r a awesome class but I hate all the running around