My airlines SOPs are to wait to see ground equipment/crew clear, complete the After Start Checklist then request taxi. We're "habituated" to hearing "After Start Checklist complete" followed by PM call for taxi.
Clearly under these circumstances, calling for the After Start Checklist before clearing the ground crew is a big no-no, it's all too easy for PF/PM to default to motor action and request/call for taxi too soon. Throw in some fatigue, slots, delay and/or distractions into the mix while you're at it.
If I'm asked for the checklist before the ground crew are clear... "standby". We all know what our SOPs are, and quite frankly I find it baffling to try and save few seconds ANYWHERE when you have people near running engines.
As with most of these SOP discussions it's entirely academic to most line pilots. Someone's crunching the numbers on which method is safer, the rest is anecdotal. We're flying their planes, we follow their SOPs and take the paycheck at the end of the month
