Can anyone with a different brand of Avalanche Beacon locate me if I were to become buried? What frequency/frequency range is used?

Just to clear everything up regarding differing frequencies, because this is a matter of life and death, here is what wiki has to say about it: "Early avalanche beacons transmitted at 2.275 kHz. In 1986 the international standard of 457 kHz was adopted and remains the standard today. Many companies manufacture beacons that comply with this standard." So make sure you know what kind of beacon and what frequency you AND your partners are using. 2.275kHz beacons will find other 2.275kHz beacons, but can't find 457kHz beacons. There are some beacons available that will transmit on 457kHz, but will receive 2.275kHz as well as 457kHz. Make sure you know what everyone is using, and check each others beacons before you get started. Practice, practice, practice. Know how to use it, and make sure your partners do, too.

Although, beacons sometimes seam to find peers (same models) quicker....

457 KHz is the international standard for avalanche beacons. All (current) beacons comply.

The frequencies are the same between brands. Anyone can find anyone.