Mustangs are about like any other breed; there are great ones and there are not so great ones. I've had 2 come through my barn. One, I bought, trained, and sold on to a girl who is having loads of fun with him now. The other is my heart horse and will be with me until the day he dies.
If you like him and get along, then snatch him up......and we demand pictures
Edited to add: As a breed, they tend to be a "jack of all trades, master of none" type of horse. They can do just about anything you ask them to and do it well enough to be competitive at lower levels if you're competing, but it's relatively rare to find one that excels at a particular discipline.
My guy is a great roping horse, but he lacks speed. He tries his hardest to be a cutting horse, but he lacks agility. His strides are very short so he wouldn't be a suitable English horse, but his gaits are smooth.
About the only thing he's really really
good at is covering country, but that's what he was born to do. He's the type of horse that can go all day and night for a week and still be bright eyed and bushy tailed in the morning.