Wireless Network Solutions for a Metropolitan Area?

An anonymous reader asks: "I work for a company that is expanding into multiple buildings within the same office park. We have line-of-sight between the buildings and are looking into wireless alternatives. Does anyone have experience with products such as Proxim's Tsunami or Bridgewave's GE60 Gigabit wireless link? The point-to-point links will need to support the usual LAN traffic (SMB, HTTP, SMTP, etc.) as well as VOIP. The buildings are not large--up to 140 users, whose main network use would be e-mail, printing, and saving Excel documents to file servers, as well as the aforementioned VOIP). Are these connections any more secure and reliable than using something in the 802.11 family of protocols?"