Well this should piss ya off, I have 2 enemy skill materia, level 27 on main character, and mid 20's on Tifa and Yuffie. Just got done Cosmo Canyon, and went back for beta.

Well I now have 2 characters with Beta, smacking close to 3000 pts of damage to enemies (well technicallt around 1500 each, since it obliterates all), and at 35 mp a pop, is stronger then any summon at this point.

Hint: I dunno who you have in your party, but I equipped elemental + fire in Clouds armor, and had him attack with Climbhazard as soon as Zolom started Beta. Yuffie & Tifa pounded I am estimating between 3-4K damage, effectively sending them out, or prompting Zolom to use Beta, killing whoever was left.