We see them often on eBay, and if it was parted out from a new KLR, then it'll likely be a good deal.
The Electrosport (formerly Exlectex, I think...) ones have sometimes been described as "unreliable," but then the next guy has no problems, so who knows? The 260-somthing watt ones have been out for a while, but the 400-watt ones are relatively untested.
Make sure you don't have some other electrical problem before you fry another stator.
Good luck.