I would say sooner the better but yes April would be favorable. Although it doesnt matter if u plan to live here for a long time of ur life....we got to get accustomed and keep moving .
I would recommend May for the best month as in April is still very cold and as we new comers to Canada will be without cars and would have to walk around more just to know better the place where we are going to live it would be better do it in a nice weather.
From relatives and friend I have in Canada they always say to me that real spring is in May there.
Decision is yours.
In May its Spring time but remember still the temp is 7 degree to 9 degree min .
For jobs landing in Sept is the best as most of the college students return back to college studies.