First off, gear on a Shaman (and on an Enchanter) does not really matter, with a few exceptions. Leveling up I had total crap for gear, and even at 60 I am still wearing several pieces of ringmail and similar junk, but not caring (see Magelo link below). However there are four key Shaman purchases, all of which are not cheap (a fungi, JBB, epic, and Torpor) vs. only one for an Enchanter, and its cheap (Goblin Gazughi Ring? their epic isn't even that great). However Shaman are good at farming plat and valuable items so this just means you'll spend more time farming if you pick a Shaman.
As far as soloing end-game content, solo leveling, and grouping, both classes are about equal. Both can solo high-end stuff that other classes can't, both can easily earn XP soloing, and both are desired in groups.
Things a Shaman can do that an Enchanter can't: SoW (and they get insta-click SoW booties), Cannibalize (huge downtime saver), heal, root/rot (Enchanter DoTs are weak), wear leather and chain armor, have more hp, slow slightly better
Things an Enchanter can do that a Shaman can't: Clarity (also big downtime saver), charm (incredibly powerful), mez, haste slightly better, illusions and faction buffs
TLDR: Go for shaman if you want a battle caster, go for an enchanter if you want a puppet master
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