Fyodor of Nmap fame has posted the results of his 2006 survey of security tools. Fyodor posted the results at his new site SecTools.org. On page 4 you'll find Sguil listed as number 85 out of 100. Unfortunately, BASE beat out Sguil at number 82. Another personal regret is seeing Argus listed after BASE at number 83. The next time Fyodor asks for suvery participation, I will have to respond!
Although the top 100 results are useful, some of the sub-categorization makes little sense. Sguil is listed in the Traffic Monitoring Tools subsection, along with Solar Winds and Nagios (?!?). The Intrusion Detection category lists BASE but not Sguil, along with Fragroute and Fragrouter (?!?). Bizarre.
Regardless, I recommend security pros familiarize themselves with all of the tools in the top 100. It makes for great discussions during job interviews, either as the employer or prospective employee.