I've been looking at both of these packs and was hoping to hear from others who have used them. They both seem pretty similar in overall volume, pocket configuration, price, weight and suspension systems with each having removable stays and a pad pocket.
But, while the Starlite seems to have a close suspension system to the MP, it isn't exact. It seems like it can be customized a little more with the addition of load lifter straps and it has those great pockets on the hip belts.
But the Mariposa Plus is slightly cheaper and it included a small pad for the back, while the Starlite doesn't. And you can customize the bungee straps on the MP.
