I don't own one but

None are made in Germany only the very TOL 800 Plus are made in Germany, not all 800 Plus.

There are 11 300 series models and 5 500 series models. There are some significant differences inside each series. These are made in North Carolina.

Best to read up on Bosch website and narrow it down some and ask more specific questions,

Both are made in the US plant and all the Bosch dishwashers germany and US now use the same pump and heating systems.
The biggest difference is the 300 are the Hi-bred tub and the 500 and up are the all SS tub. That and cycle selections.

deeageaux - Thanks for your response.
I will narrow it down and come back with more specific questions.

jakvis - Thanks for letting me know about the pump & heating systems being the same, now.
I will look in to the different tub materials. Do you have an opinion on which is more durable? Our city has VERY hard water if that makes a difference.
I'll also check out their cycle selections. Off hand, I don't think I'll need/use extra special cycle selections.

The tub won't make the difference in washing but the new all SS models are a bigger tub, are quieter with a few more cycles, and better racks.
Both are excellent d/w's and both will do a 160 F wash and rinse.

jakvis - Thanks, I appreciate your input. I'm glad you feel both are excellent dw's.
Quieter and better racks would draw me toward the all ss models.