Definitely go for Canada (personally I'd try to do both countries for two years each, clue in the username), but check out the location (and driving distances, airports, flight costs to the UK and to where you might want to visit, etc) before you agree if you're planning to do a lot of travel or have people visit you.
I've been in Ontario for over a decade and these wonderful reports of the education system are unrecognisable to me. We've had many incredible teachers but my DS9 and DS12 can barely write (as in form letters that don't look like they've been written by a 4yo). All my DC are amazingly self-aware about their emotions, but academically are way behind their younger English cousins. Tall poppy syndrome is very real, and in my area you are absolutely NEVER EVER ALLOWED to do any work above grade level if even identified as gifted. SEN provision is drastically underfunded (and I have heard all the horror stories about UK parents having to fight tooth and nail for SEN provision--but at least there's some to fight for!). No schools in my area have pools or nice tech/science facilities (except the private one), but they do have decent playgrounds, and there don't seem to be rough/undesirable schools in the same way (lack of yob culture definitely helps with that, I think). Some or all of this will probably vary school board to school board, and certainly province to province, so it's probably worth your while to join some fb groups for the places you might live.
But you're not doing it for the education, you're doing it for the life experience, the travel, the exposure to different customs, the adventure. If the schools where you end up are like the ones near me, you can teach them things like times tables and handwriting yourself. So I would go for it without hesitation!