The Pro3's are farily new to the market. They are packed with electronics. Eheim are renowned for pumps and filters, in fact they made their name with pumps and moved into filters as a more "on the side" project that grew somewhat arround 30 years ago... Something Eheim aren't remowned for is electronics, and the Pro3's are packed with them. I'd wait and see if they become an issue for those that have them in a few years time before putting cash on a pro 3 myself, especially as they are likely a part they have had built for them by the cheapest supplier going at the time due to the fact that they have no in-house electronics division, but each to their own...
The specs of the 2075 are suited to your tank. I would go with the tryed and tested 2028 though myself, it should be cheaper as well as having less "gimicks" that could go wrong with age. Do you realy see yourself needing that built-in flow controlling computer anyway?
All the best
Rabbut