Which A/C system best for Texas climate?

I'm in the process of buying a home that will take a bit of "fixer-upper" work, including upgrading the Central A/C system. The current system is an undersized Bryant Heat Pump. I live in North Texas, where we have drier climates and sweltering summers. I realize specific models will depend on several factors, but I want to know which brand names my fellow North Texans have found to be most dependable. I'm pretty disappointed with Bryant systems nowadays. Every single Bryant system I've ever had that was SUPPOSED to be able to handle my cooling needs, be it standard A/C or heat pump, failed to keep up in the 95+ degree Texas heat. At this point, I'm not concerned about price. I want dependability!