Oman there is a problem in accomadation not that its costy its not available, plus if u live in Muscat there is not much to do.. they have 2 malls... but u can go to Salal which is 6 hours flight from muscat ... if u r planning to live in Madinet Al Sultan then u will enjoy it so much its an amazing area .. if u r lucky enough to find accomadation .. plus its expensive in tht area...
as for Doha the accomadation is expensive, the cost of living is costy as well.. but there is a little more to do than Oman .. u have resturants, cafes, malls ..
so its up to u ..
if u have the chance to visit both countries before u decide it will be better.. Good Luck