Depends on which part of the antler I am working. The disk at the end where it joins the skull is good for netsuke but is very hard and responds well to scrapers, the stem of the antler, all the antler really has a useless soft core (pith) which you must remove - it is so soft that you can flood it with warm water and scrape it out with a spoon, This leaves the wall of the antler which is a dream to carve, and which you can carve with standard wood-carving tools as well as scrapers - I have a pin-board of carved antler and bone items, mostly bone items, and none of them by me, but it does show what is possible. https://www.pinterest.co.uk/avenuew/carved-antler-and-bone/
The stems cannot be heat-formed and so lend themselves to tubular forms - traditionally, needle cases, salt cellars, powder horns. If you use a palmate antler - moose or fallow deer for instance, the palms are great for relief carvings - I split the palm and make carved inlays which are only about 1.5 mm thick, many medieval 'ivory' carvings are in fact antler. The palms can be heat-formed, up to a point, are flexible, up to a point, but can snap without warning if you get clumsy with them or they dry out too much.
Biggest down-side is it can be difficult to colour, it resists many stains and is translucent. This translucency can make for an interesting carving experience if your eyes are tired or your lighting is wrong.
Biggest upside - it accepts the very finest of detail in a way even box-wood doesn't; it is astonishing how fine you can carve it