We're just setting up a 900mhz WISP with the SR9's in a very rural area, and so far NLOS performance has been great and reliable. I can get three about 1 to 1.5 miles of solid trees, and even through some terrain issues. Ive also seen 4 miles or more NLOS if the path is mostly open fields. No experience with urban setting with buidlings. I suspect your main issue would be multipathing off buildings and such, I can't imagine homes being too much of an issue. Another concern would be noise. If it's out of band noise, the Ubiquiti cavity filters will clear it up, in band noise may prevent you from using 900mhz. Only way to tell is to order a couple of cards and give it a shot. Talk to Paul or Carl at Streakwave, good guys, and they will give you a good deal.