What gives ebony a bad reputation is that too many new makers put it on a handle and go straight to the grinder to hog it into shape, rapidly sand up the grits, then power buff it to a high shine. This drives out all the resins and heats the wood up a LOT. The wood was lovely when done. but cracked or checked later on. The problem isn't the ebony, it was the techniques used to work it. Ebony is often called "black ivory", because of the way it looks and how it is worked. Treat it like ivory and you will get great results. Mistreat it, and just like ivory, it will have cracks and splotches.
Grind ebony slow and with fresh belts. Sand to a fine finish and buff gentle ( or sand and buff by hand). Paste wax puts and keeps a lovely shine on ebony. Oils should be avoided. African blackwood is a good ebony alternative.
A few words about ebony:
Many carved "ebony" objects are not ebony. Some is dyed African hardwoods, and some is ebony relatives dyed or painted to look like Gabon ebony. Ebony is a large family, and most is not black. Some is white and black striped. Persimmon is an ebony, and has been dyed and sold as "ebony".
A lot of ebony sold by wood suppliers, even the biggest ones, is dyed. Some is also not fully cured. Be cautious of heavily waxed ebony, as they use a black wax to make the blocks look darker. In grinding/sanding dyed ebony, you may actually stain your hands black when working it. Some of this wood isn't even ebony at all.
Buy ebony from an exotic wood dealer who knows his ebony. He will know how long it has been drying and where it came from. The big name wood suppliers and woodworking chains often just buy whatever is offered at a good price and have no idea about what it is or where it came from. They may label it all "Gabon" ebony. I have found that a good wood supplier will happily answer this question with yes, "If I am not satisfied with this wood, will you replace it or refund my money?"
Good ebony is not cheap...and if it is cheap it is almost assuredly not good ebony. Old ebony furniture is often quite brown once you cut it up. The wood may or may not be ebony, and the lovely black shine is usually a varnish or other surface finish. Even expensive pianos are like this. It is always worth the effort to see if an old thing can be re-purposed, but be aware that it may not look the same inside as it does outside.
Ebony will turn a lighter brown and/or show stripes when sanding, but should turn dark again when finally sanded to a fine surface, then buffed and waxed, if it is the real deal.
Sand to as high a grit as you have for the best shine and depth of surface. The better the sanding the better the finish. 1000 is a minimum, 8000 is not totally crazy. If taken by hand to an 8000 grit finish with the 3M papers, a hand buff with wax on a soft cloth is all that will be needed to finish the job.
Avoid power buffing with white rouge as it can make tiny white flecks in the shiny black finish. A clean muslin/linen/cotton buff with some carnuba type buffing wax on it is great for getting a high shine on well sanded ebony. Use light and quick buffing passes, and use the very minimum of any compound.
I was at a wood supply store once and they had blocks of wax coated ebony. The wax was completely black and very thick. I asked if they had some without the wax on it. The salesman said the wax prevented the wood from cracking. I asked what would prevent the wood from cracking when I made something out of it. He looked dumbfounded! I have also asked sellers online to sand the wood to a smooth surface without wax and send a photo. Most refused, as they knew that the wood would be brown, not black.
