The sophisticated trait is pretty useless compared to the traits of the other undead races, since it grants poison resistance which undead already have at 200%.
The fire resistance is nice, but the extra poison resistance is completely useless because you can't go above 200% anyways.
Every other race has something worth choosing that race over, but undead lizards don't have any particular advantage over the other skeletal races.
Side note: enemies that otherwise don't know you're undead somehow know to use healing magic to damage you? I thought the point of concealing yourself as undead was to prevent that?
