While I haven't played 2k points yet to know the difference, I have played about half the armies at 1k. My club has DE, HE, WE, TK, Brets, O&G, and Dwarves. My experience (~30 games) has shown that the proper question here is what armies don't do well at 1k. Most of the armies are fine, but TK and Brets struggle because of the amount of points that must go into heroes.
However, the most versatile armies I've seen at 1k are HE and WE. Both can go from shooty to assaulty and from static-ish to insanely mobile. Granted I play WE and my most frequent opponent plays HE so that could have something to do with my opinion on the subject.
I'm really looking forward to escalating to 2k soon.
They can all do well if you know what youre doing with each. If you are looking for a good army to begin with then I strongly advise that you choose one that you like the look and style of. Tactics and victories will come later, after playtesting and practise and refining your army to match you.
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