Sapele is perfectly good, just harder to work. I find cedrela and honduran pretty easy to work in comparison, especially around the heel. I haven't used sapele a lot, perhaps on 10 instruments. If I come across straight grained stuff I buy it. It's probably the easiest suitable neck wood to source, it's commonly used by the furniture makers and joiners. The neck for a uke is really a small off cut for the joinery trade. You should be able to get it quite a lot cheaper than that ebay listing if you hunt around.