Originally Posted by
vantony
I have option of EWR instead of LGA. Would you think that's a better alternative?
There are also delays out of EWR (in fact I had a 5 hour delay a few months ago on the exact route EWR->YUL). The argument for LGA is that there is more frequent service to YUL so you're better protected if your flight goes mechanical or gets delayed. The argument for EWR is that AC operates a non-stop to YVR so if things go squirrelly you'll have a better option available. Also EWR is a major hub for UA meaning you'll also get a decent amount of intra-US connections to YVR (i.e. EWR->SFO->YVR or EWR->ORD->YVR, EWR->DEN->YVR, etc.)
On the whole, you should be fine with LGA. As others have pointed, AC's network is fairly extensive and even if things go a bit squirrelly there'll be a route to get you where you need to go.
-James