Hobbyist engines with no energy loss should power 2 and 2/3 chests per engine... unless the chests use more than their base 3 power units when not connected to a controller.
With a controller using disc drives becomes rapidly more efficient. Each hobbyist engine can power a drive and 10 1k discs on its own.
ME Chests use 1 unit empty and 3 units with a disc in.
ME drive uses 2 unit of power and a scaling amount for each disk it holds. Amount is .5, 1, 1.5, and 2 AE units per disk relative to its size (1k, 4k, 16k, 64k).
1 MJ = 5 AE power units.
A drive with 10 1k discs, access terminal, and controller is 14 AE units ~ 2.8 MJ/t. So two hobbyist engines could run the network. Each disc can hold 65-127 stacks of items... Pretty good storage running on early game power.
On resources, ME Drive actually looks cheaper than a chest. But you also need a controller and interface to make use of a drive... but you will need those things eventually anyway. Chests have a use, but in most cases drives are the way to go.