HIFU is done all over the world, except the United States where it is done only on an investigational basis. I am familiar with the Sonablate 500, and have seen the Ablatherm in action. Both will likely give similar results. The Sonablate is more compact and more portable. The Sonablate has a color Doppler ultrasound built in so that the neurovascular bundles can be identified, and you can treat around them.
Experience does count with the treatments as a large amount of the treatment time involves appropriate programming of what to treat. Being able to "read" the ultrasound image is of utmost importance, as well as positoning the prostate adequately, power setting, etc.
As far as locations is concerned, I am familiar with Cancun, Puerto Vallarta and Nassau. The hospitals are clean, the water is safe, and you will have an American surgeon as well as American staff.