Back to the original question…
I ride an OTTB. He’s got a great work ethic and really seems like he moves on down the trail. Lots of other trail horses (even the gaited ones) canter to his trot, so I think he’s pretty good. Until an Arabian comes cruising by us at an effortless trot. Okay, maybe it just seems effortless. Not every Arab is suited for endurance, just like not every TB is cut out to be a race horse. On average, though, I think Arabians have long strides, a natural curiousity that makes them want to head down the trail, and a decent work ethic that makes them excited to start work (unless they get over trained).
I am currently fostering a 14hh, 14 year old Crabbet-bred Arabian mare until she learns better manners. She’s easy to ride, but her ground manners need to match her trail skills. This mare likes to hang back and go second, moseying along at a slower walk. She doesn’t seem to be a horse for any kind of distance riding, since she’s not that interested in moving along. If the lead horse balks, she’ll happily go past and do an obstacle first, but then she wants the other horse to lead on down the trail again. IOW, she’s great for an advanced beginner to ride. 
One day I rode her on the trail with an OTTB (another foster horse). The little Arabian mare had hung back and would trot every so often to keep up with his faster walk. Then he started trotting out in the open while my mare was snatching a bit of grass. When she realized he was getting farther away, she went into a beautiful, ground covering trot and quickly caught up to the OTTB, never even breathing hard. The other rider remarked how fast the OTTB’s trot was, and I had to chuckle. Now I know why those Arabs cruise on past while their riders smile and nod at me! At the same speed, my OTTB would have been jarring me on every stride, since he has a strong bounce in his step.
Now, when it comes to a flat out gallop, my boy pretty much passes everybody in his line of sight. But who can gallop for 25 miles? His most efficient gait seems to be the hand-gallop, so we make up for our lack of trotting speed in the open (not necessarily by my choice). I have yet to see whether riding his/my pace will last for 25 miles and whether he will pulse down well, but I can hardly wait to find out.
In the mean time, I will be smiling and waving back to the people cruising by on their Arabs. I’ll stick to my 16hh OTTB, even though we won’t be finishing in the top ten. I’ll be riding for fun, and my OTTB will be going for his own reasons (I think he thinks we are actually racing). :winkgrin: