I would say it depends on your budget. The "Best" will cost 10 times more than what you could get away with. Personally I love my DBX Driverack, which is medium quality/price. Some people swear by Behringer Ultradrive. I would say that the features you need to run any PA would be a crossover and on each output you will want time delay, limiter, and eq.
And don't forget noise level, which can be checked by turning on your system and without input turn everything up full. You will be surprised sometimes as to how much inherent noise there is. A higher noise table will reduce your headroom.