Pros
Ecolab is a good, solid company. It's not "Sexy" - not like a dotcom or ultra-high-tech or anything - but they handle the blocking and tackling of their industry really, really well. They are focused on solid, sustainable (economically AND environmentally) growth. They don't go looking for huge splashes, they just focus leading their industry and serving their customers well. And it's amazing how powerful they are in their market segment; they dominate bigger, better-known companies in terms of market share. The benefits are amazing, the salaries decent. The culture is a little "relationship-based", but not to a stupid extent (like United Healthcare). In a city full of badly-run corporations, Ecolab is (so far) a joy to behold.
Cons
Again, the corporate culture is very relationship based. People tend to stay at Ecolab a looong time, and getting things does IS often a matter of "who you know" within the company. This isn't all bad - it's not like everything about the company's future is decided by a bunch of morons on a golf course (see: United HealthCare)
