That Dynamite Prophet Precept is right on par with other 80w chargers out there. Again, for $50, it's in the same price range as anything else out there (80w chargers). Just make sure it has a storage charge function as I think that would make great charger for general use. I would look at some reviews for the Prophet Precept, but I just took a quick glance at it, and it seems to be the same type of four button charger that I use.
Charging a 5000mah pack at 5amps would take roughly an hour to charge the LiPo battery if it's almost fully drained down somewhere close to 3.2v per cell. It will take a little longer to charge, but highly recommended, if you balance the battery also. Most of the time I crank up my charger to 6 amps (that's all she got) when charging my LiPo packs.