I think it depends on which creams you use. Sudocrem is a multi-purpose cream from nappy rash to pimples and bed sores. Metanium is designed for when your baby has nappy rash, and is sometimes recommended by Drs. Although, Vaseline can be recommended by Drs if your baby has a bad nappy rash as it has the least amount of ingredients: petroleum gelly. Vaseline, Castor Oil and Zinc cream or Bepanthen are gentler than Metanium and Sudocrem, and I would consider them to be non-medicated.
Both of my babies have extremely sensitive bottoms. We used Sudocrem with DD pretty much from birth 'til she developed a teething nappy rash at 10mos. Then we had to try everything under the sun and found and settled on Vaseline and Bepanthen as the best. I use it at every change, but that's because of my children's skin. I attempted to forgo with DS when he was born earlier this year, but that didn't work out too well. With Sudocrem you only need a very teeny tiny amount to cover baby's bum (skin should appear slightly glassy). Although the consistency is similar to Desitin, it's design is to be used sparingly wheras Desitin tends to be the more the better.
Good luck!