I am not a woodchuck either and I don't have (yet) any neem handled khuks, but looking at the beautiful pictures Yangdu posts, it seems to have more pronounced color and figure than most of the regular wood used in HI khuks.
I myself like the look of satisal (East Indian rosewood, Dalbergia latifolia), its cousin, the sisau (Dalbergia sissoo), rakta chandan (red sandalwood, Pterocarpus santalinus), and that of the walnut (Juglans regia ?).
Satisal, sisau and rakta chandan are all leguminous trees, i.e. nitrogen-fixing plants belonging to the Fabaceae sensu lato (legumes or pulses in the broad sense) family. Many of the tropical hardwoods are leguminous trees, like cocobolo (Dalbergia retusa), African blackwood (Dalbergia melanoxylon), Brazilian rosewood (Jacarandá, Dalbergia nigra), Honduras rosewood (Dalbergia stevensonii) etc.
According to internet sources, these should be harder woods than the neem (Azadirachta indica), but neem is not a softwood either, since it is part of the Meliaceae (mahogany) family.
As for khuk handles, I would be interested to know, how durable is neem in regular hard use or when exposed to typical winter cold.
Just because neem is somewhat softer than satisal, does not mean that it cannot have for example even better shock resistance.
Also, due to its natural high resistence to fungal decay and insect attack, it may be ideal in very humid enviroments.
It would be interesting to see some comparative testing to find out which Nepali wood would be optimal for user khuks in different enviroments (wet, dry, hot, cold).