I'm loving my Orea; it's replaced the V60 most days. I haven't bothered with flat filters because of the negotiator tool as well, but Kalita filters have been working fine. One thing I've found is that some coffee will stay between the brewer and the filter without flowing down. I'm not sure if tipping the Orea and adding that 'stuck' coffee is helping or hurting the cup, but once I get a TDS meter I'd like to see how much dissolved solids (or passthrough water) I'm adding at the end of a brew.