I leveled as a fire mage for ~25 levels, switched to air for another ~25 levels, and got around to trying earth. It took a bit to grow on me, but now I play as an earth mage, speccing to grandmaster in Earth and also in Arcana.
My preferred weapon is the staff. It’s two-handed, so eventually when I try for fancy cultural weapons or legendary ones, it’ll be half the cost of buying/making a main-hand and off-hand item. That is a lesser concern… I settled on staff because across all elements, it has the greatest number of skills I like.
This is important because elementalists can’t switch weapons in combat! Annoying, and I thought this was a bug for sure – originally I swear the character sheet let me load up a swap set, but now it doesn’t and I have no screenshots to show otherwise – but after digging around, it seems that both elementalists and engineers can’t weapon swap in combat because those classes have something else instead: attunement swapping (for eles) or kit/belt swapping (for engineers). I’m not sure it is a perfect substitute but whatever.
As for staves, Fire has its impressive Meteor Shower; Air has Chain Lightning (good for hitting 3 foes, although sometimes this draws an extra add into the fight), Gust (interrupt/push back) and Lightning Surge (blind); Water has lots of healing with Water Blast, Geyser, and Healing Rain; Earth doesn’t have flashy effects but it does do great damage with bleeds from Eruption and Shockwave. I love watching the damage number “erupting” from the mob like a tiny volcano. The bonus toughness helps (just a general sense, I didn’t do comparative tests) too.
My playstyle doesn’t involve too many attunement swaps – generally in a group event I’ll start out trying to stack bleeds and then switch to Water to lay down a regeneration circle or two. It’s fun and I feel useful, hanging towards the back and helping pick off adds and rez others.