It should be as effective, if not more. This is because you get a more concentrated effect where you need it, without an increased dose.
As for expense, expect it to be high, since it is new and no generic available. I am not sure how your drug plan works, but I get brand name non-formulary drugs for the same co-pay as other brand name drugs. But, this is only true if my doctor writes the prescription with exception codes that allow for that coverage. I suppose it is easier for my doc, because I have Kaiser, and the pharmacy, medical care, and coverage provider are all integrated.
Have you considered hydrocortisone retention enemas or Cortifoam enemas as a more cost effective alternative? Yes, there is more systemic absorption compared to budesonide, but being topical over a smaller area, this is reduced. Once in remission, you just reduce to the lowest frequency that keeps you there. Could be once a week or less.
Jan