The flow rate is an interesing one, as the stated flow rate is the actual flow rate, so could be a lot more powerful than given credit for.
I know someone who has been running the G3 and G6 for months, and with no reduction in flow rate either, indicating the pump is very high quality (or their tank has no mechanical load to block the filter!)
For me, the conductivity meter is questionable. It's the main reason the price is so high, as I understand.
I would have prefered to have seen a built-in heater or even CO2 test (pH probe/ref. KH solution).
They do look great and the user-friendly media system is a great idea, allowing the filter to be cleaned in seconds, rather than several minutes + lots of mess.
I think the best thing about this filter is the new ground it has broken with aesthetics and user-friendliness. If developed in accordance with some of the feedback Hagen have received, this could be a product to watch and certainly one I'd consider.