Thanks all for the super useful thread as I was lurking while awaiting the approval of my own application. Registered and am posting hopefully for the benefit of other applicants...

Application submitted online: March 8, 2018
Conditional approval: April 20, 2018 (28 business days, not counting Good Friday/Easter Monday, as noted above, it seems that we can reliably expect a couple of weeks longer than the CBSA estimate)
Interview: April 20, 2018 in Ottawa (about 30 minutes after conditional approval email which must surely win a prize... and the next available slot was over two months from now, ouch)
Final approval: April 20, 2018 (about 20 minutes after interview)
Card received: May 1, 2018