I’m not really familiar with Deseret besides the history and concept. It was optimized for typesetting, lacking ascenders and descenders that tend to break off of metal type over time. That makes it hard to read. It sure has an aesthetic though, and I fancy it would make a great arcane glowing script flowing across a magical obelisk. Shavian was made for the pen. Every letter can be written in a single stroke without lifting the pen, and it uses ascenders and descenders to make the coastlines of words more distinct. Shavian also strives for a “mid-Atlantic” accent in its spelling. This does create some issues if, like me, your dialect uses the same first vowel in cot, caught, father, and bother.

Of the two I think Shavian has a bigger following.