BUDGET: Go with netcages. Cheap and efficient. Glass enclosues MIGHT be more expensive, espeically with a top piece. Unless you already HAVE an aquarium laying around, then... we have a winner.
HUMIDITY: A real challenge with netting. My net cages under lamps can go from 95% to 10% in a little over a day. On the other hand, even with good ventilation, if I don't get it juuuust right, my glass enclosures will eventually have to deal with mold (sooo many dead fly parts).
VISIBILITY: Hand's down, glass (or plastic) wins. Not only becuse it's better viewing through ONE pane of glass than the wrinkled plastic, or netting, but the net cages stain. Some of the red vomit stains are hard to get out, as are food coloring from some brands of Fruit Fly mixtures, etc.
HANDLING: As Phil mentioned, glass cages can't compare with net cages, for sitting them in your lap, and rocking gently while you adore your little babies.
ADVICE: Eventually, if you stick with the habit (sorry, hobby), you'll have both. I've really warmed up to very small monarch cubes for new arrivals. Nothing in the cube - just nymphs and fruit flies. I mist it (often) and sometimes wrap it 3/4 of the way in a plastic bag (to keep humid). They fatten up, and cannibalism is diminished (you can see your hungry brother coming). Heat trasfer is great. But once they're stable, by FAR, my favorite is glass tanks with sliding front doors (and a creen top). I HATE the
sliding screen TOPS. SO hard to get open without squashing someone.
Good luck!