Dude - just go get this:
A 20 gallon roughneck container - with lid
an air pump with air hose & 2 stones
200 gph water pump
pvc - tee w/threads in bottom, nozzle to screw in tee w/1/2" barb, 2' of 3/4" pvc, 2 end caps
6-8 3 3/4" net pots
8 micro sprayers
you can get all pvc parts at Home Depot
get irrigation parts at bghydro.com
a few 150 W cfl's - you're in business
after you have everything do a search on here for how to build aeroponics and you'll see how simple it is to buid your own!!!
Minus the water pump, pvc, fittings and spray nozzles and you've got yourself a Deep Water Culture for about 40 bucks.
Figure out what you feel is good, then research. The AeroGarden is a great learning tool, but is definitely undersized. If you're gonna go mini, even smaller. Like was said before, one plant is probably gonna be your max.
Not saying the AeroGarden doesn't perform, cause it does. I yielded 5.5 oz off three plants in an AG Deluxe with four 65W CFLs.
With an eighteen gallon rubbermaid tub, you can get four plants in there and end up with some pretty decent yields.
That being said, go with what feels right. Personal experience can only add to the happiness.