I beg to differ on the canter being smoother. My Foxtrotter has the funkiest canter I have ever ridden! They also tend to go into and out of a pace when you get to the speed of a canter. My non-gaited horse (a Mustang) has a smoother canter, hands down.
The main problem I find riding a non-gaited horse with a gaited horse, is the "flat walk." I call it the speed walk. A lot of gaited horse folks seem to push for the speed walk, and it makes it really hard for most non-gaited horses to keep up. Because their walk is hard to match on a non-gaited horse, and if you trot you are going too fast. So it's a weird in-between speed.
I find the trot matches up to the foxtrot or running walk speed wise, but you will be trotting while they glide. I finally gave in and bought a foxtrotter so I could have a gaited and a non-gaited horse, so I could match speeds with both groups of friends I ride with. But my Foxtrotter isn't really set in her gaits well, so I drift in and out of all sorts of speeds and gaits. It's really weird when you are used to having only 3 gears, lol!
PS. As a breed I love Arabians, I've owned two. :)