For small installations (without a WLAN switched infrastructure) or for specialized environments like outdoor WLAN deployments, go with the laptop-based tools for your manual site survey.
And if your organization is medium to large with a specialized environment or with applications that require large WLANs or the planning and support of a repeatable enterprise-wide WLAN, a site-survey modeling tool is best. This tool is also useful if you need an accurate preinstallation estimation of how many APs you'll need and where they should sit, for example, or if you want to execute "what-if" testing without affecting the production WLAN.
Cornell W. Robinson III is an associate and wireless security consultant for Booz Allen Hamilton and a contributing freelance reviewer for Network Computing. He previously was an adjunct professor at Syracuse University and a manager at the Center for Emerging Network Technologies there. Write to him at firstname.lastname@example.org.