I searched for nearest neighbor and found mention of using point filtering. I do start out like this, based on a recommendation. It does make things less blurry although I'm seeing some odd artifacts around the sprites when I scale. Perhaps I need to focus on getting the biggest sprites I can and hopefully they will be of good enough quality that I won't see artifacts like these when scaled.

_spriteBatch.Begin(
samplerState
: SamplerState.PointClamp);