The ranch that my brother manages raises what I think are Dexters (at least they look the same, I had to google them) and they produce a nice crop of babies every year. Most of them are very mellow and just like to kinda go with the flow. Some of them can get incredibly large; there were some momma cows this spring during the branding that were almost as big as my horse and probably weighed more. We also get a bunch of yearlings every summer from a feedlot and some of them fit the profile for Dexter cattle. They do well and fatten up quickly. I have not really noticed any big health issues with them either except the occasional pinkeye or foot rot.
Good choice.