Las Vegas to Toronto

We'll be heading to Toronto for some concerts in Nov. We don't fly often, but we tend to fly Delta when we do. They've had the best schedules for Las Vegas to NYC in the past with non-stop flights and we liked Delta when we traveled with them.

I was looking at flights for the Nov trip to get an idea of prices. Delta's website shows a handful of non-stop flights, but in small print it says "Operated by WestJet." Is WestJet any good? The handful of reviews I've seen are not good.

We don't care about status. Who has the best first class from Vegas to Toronto?