I got my master's from UC Irvine (though not in business). It's a young school with only 40-yrs history and has great potential; many programs are rising in naitonal ranking. UCI's business school used to be so-so (probably ranked 40 or so), but they just got a huge amount of donation from a business person and thus they paln to expand its program, recruiting more prestigious faculty members and taking in more good students. They want to enhance its MBA ranking by raising the average GMAT score of their incoming students, and I guess that's why they would send out so many application invitations.
BTW, Irvine is a beautiful city; very clean, very safe, and with very nice weather.