My wife and her daughter came here in November 2008 after the usual K1 Visa wait. Her interviews were pretty painless, and now we just need to remove conditions in 2011.
My Wife became a Citizen in August, 2013. We applied for her Mother to come here on an IR5 Visa. She just had her Interview on June 11, 2015 and will pick up her Visa in a few days. She plans to come to the USA around September. Her Interview was only 20 Min.