I'm right now in the process of making a decision on hand rails. I've given Ipe, (Ironwood, Brazilian Walnut, all the same), some thought but damn that stuff is hard. Near four TIMES as hard as teak. Old schoolers use brown boot polish on the stuff, presumably because varnish or oil won't soak into it. Be very tough to put that 10 coat Bristol varnish finish on that..
Sapele is starting to look good for this. Beautiful, strong, more available than teak. And without chewing up every bit and blade on the farm trying to work it..
(And it is a type of mahogany if I remember correct).