That would depend on your radiation environment. Not every
SOI is naturally hard to total dose, sometimes they are much
worse than junction isolated. Of course there are other forms
of radiation and radiation responses where SOI excels.
If you were to attend the conferences devoted to the
subject, you'd find that SOI is used for only a modest fraction
of the space IC components. This is due to cost and to the
lag between commercial leading edge, and bringing out a
reliable SOI version of the same node (SOI often adding
one more thing to go wrong).