hedonist222 The best way to think about this is not worrying about the maximum flow rate of the pump too much. This just affects how quickly the headspace fills above the portafilter and the soft/or not start on the coffee puck. The E61 actually has a preinfusion chamber, just to mellow the rapid output/pressure rise of the rotary pump once the headpace is filled.
If you extract an espresso with 40g over 30 seconds and if we assume that’s 38ml of liquid , because there will be some solids in there. That’s a flow rate of only 76ml per minute.
Whether the pump is capable of 1000ml per minute or 200 ml per minute, doesn’t really make any difference, because at the same pressure the coffee puck determines the flow. So Vibe pump vs rotary makes little difference…The main difference: vibe pumps are usually much noisier than a rotary (the exception being the Lelit quiet Vibe pumps, which are significantly quieter than the standard vibe pump, but not as quiet as a well implemented rotary pump)