1. I prefer drip over sprays for a few reasons. First, especially if there are already plants installed, it won't damage them during sprinkler installation, because the drip line stays above ground. I think you are more likely to notice a problem with your drip line because everything is exposed, whereas the sprays, with the exception of the sprinklers, everything is underground. Secondly, most delicate plants do not do well with water being sprayed on them, this can cause diseases on the foilage and can even kill the plant over time. Drip systems are more efficient because they put the water where it is truly needed, at the base of the plant, directing the water at the root system. For 1000 Ft. of drip, I would suggest two zones, depending upon the emitters used.
2. Coming from a professional, I wouldn't trust anything that isn't of professional grade, and I certainly don't think that Orbit products meet the professional grade standards. You really have to watch the Rain-Bird products as well, because they have both home improvement store models, and Professional series products. Orbit is the Hunter Irrigation home improvement store grade products. Stick with either Hunter or Rain-Bird professional series.
Also, you'll want to make sure that a backflow device is included and properly installed to protect your drinking water supply. Sounds like you've got some decisions to make, and quite the investment. I would take the time, spend the money, and do it right the first time. Good Luck!
Tony Posey
Ridge Run Landscapes