All i really eat is Cereal and Protein bars, look in my cupboard and theres about 7 boxes of cereal and around 200 protein bars.
i only buy the real brands only because i get them for $1.00 each at the deals only store, they arnt out of date or anything, most of them were just overstock or had their poor lil cardboard box dented.....damn good deal compared to $4 to $5 in regular stores.
but for your question MSB, 80% of the time i feel the 3rd party cereal is dead on balls the same as the regular stuff, but every now and then i find one that u just know isnt anywhere near the good stufff.
cereal is mostly marketing, the boxes that cost more are uppin the price because of their brand names(kellogs, Lucky Charms....etc)
its kinda like T-shirts, you can buy a plain white off-brand T for $5, or buy the same exact plain white T for $20 with a small Black Nike logo on it instead, your basically paying the extra $15 for the brand name, you dont think they spend billions on advertising for notin do you?