Vantaggi
Ancestry.com develops products that actually mean something in peoples' lives. Benefits have always been great. Salaries have been at or above competitive rates as far as I have seen. Time off policy has always been generous. Most of my coworkers have been talented, smart, and nice to work with. The technologies we use are interesting and provide ample professional development experience. Great company mission. Great work/life balance is possible with flexible hours and occasional remote work possible. Building Ancestry's products is fun because they are challenging and interesting to build, and contribute something meaningful to the world--not just building widgets at yet another widget factory. It also helps that Ancestry has experienced healthy growth for as long as I've been here--through the recession and all. This is a thriving company with a solid business model. Current top management seems to make great decisions.
Svantaggi
From an engineering perspective: Ancestry supports a large suite of products and changes are slow. We sometimes lag behind in implementing newer technologies because most development involves enhancing existing properties, not building brand new ones. This type of work involves overcoming some inertia, which makes change slower than at many smaller/startup companies.