I am strongly biased towards Franconian Bratwurst and spoiled for the other varieties.

I personally think Nürnberger are a very good Bratwurst species – flavour famously compressed in a shape small enough to fit through a medieval key hole to circumvent medieval sales restriction, or so the myth is told.

My absolute favorite are Coburger. These are Thuringian sausages grilled with pine cones as burning material. The pine cones give a very distinct flavour to the sausage. As you have to visit the marketplace of Coburg to get them, this might be quite an effort. Coburg is not on the Europe/Germany-in-x-days tours list, but still a nice town worth a visit. (Especially if you are aware that in the 19^th century the main export article of Coburg used to be princes and princesses and every single royal house of Europe is Coburgian, sort of. And no, I'm not from Coburg.)