What are the little plastic cups for? What are the dimensions of the units?
derricktung is correct - they act as a mini greenhouse to keep a moist environment while the seeds germinate and delicate seedlings grow a bit (can tend to be a bit dry in winter). My wife had just taken the little domes off and placed them by the side of the plants - they will be removed now as we no longer need them.
The footprint is relatively small - approximately 18 inches long x 10 inches deep x 12-20 inches tall (telescoping light fixture on some units allows plant growth to a significant height)
They sell hydroponic basil at a local grocery store, and it has very thin and fragile leaves and no flavor. Anything you can do to grow it better?
The basil tastes really good - I think better than the fresh basil you can purchase in the small packets at the grocery store - the leaves are thicker as well. Because of the variety of basil species (Lemon, Thai, Napolitano, Marseilles (French), Genovese (Italian), Globe and Red Rubin) most of which are not readily available, growing is well worth the effort - they each offer distinct flavors. Along with the seed pods comes the liquid plant food that you dump in when filling the unit with water.
We usually do a couple of plantings through the winter - the second planting will also yield herbs and tomatoes as did the first, but these we transplant outdoors in the spring when it warms. We did that last year, and just now as the snow is beginning to fly are we out of tomatoes. The flavor of the tomatoes grown entirely indoors is comparable to those that spend the summer in the dirt outside - I just love to pick the plentiful fruit directly off the vine and pop them into my mouth for a burst of tomato flavor.
The one thing we have noticed after doing this a few years is that the plants outside in summer regularly are much more bountiful.