I've made a few pieces of outdoor furniture from Ipe and it holds up extremely well for that but I think it would be one of the last woods I'd choose for dining table chairs. For one thing they'd be awfully heavy. Plus it dulls bits/blades like nothing else. My experience with it for glueing and staining have not been very positive but I've read other forum posts with apparently fewer issues there. Plus it's already much darker than the teak. It's definitely cheaper than Teak (which is why I used it instead) but I think I'd pass for this application. Just my 2 cents. Wish I had a better suggestion but I think I'd bite the bullet and stick with Teak.