I assume the WL 10000 is the older "paint can" style. One drawback, IIRC, is that it's more difficult to attach a softbox. An umbrella works just fine. I would suggest the WL Ultra if you can find one at a good price. I don't think the Alien Bees are within your budget.
Repairs on many makes can be problematic. I've come across more than 1 "orphan" monolight that no longer has parts, including flashtubes, available. Paul Buff (who makes the WL and Alien Bees) has a reputation for great service and continued parts availability. I'd be concerned about the one from Adorama.
Other options might include the smaller Novatron, Norman, Speedotron pack units if you plan on multiple lights. Even the low end units might stretch the budget, but you would have 2 lights. But some low end pack units have limited light controls.