We use Juniper Routers at the Border Network, on the core Network, and we also have some models that are used as Firewalls (UTM). I've been a user of Juniper for a while now, and even had a development branch in production, called Olive. The stability of their products is what drove us to choose Juniper as the main provider for Network Communications across the company.
There's a vast number of options, so you can implement Juniper Routers in any scenario. Of course, the enterprise option is not for the small company, unless they need room to grow. Bring it on for your highest amount of bandwidth, Service Providers that need to peer with many different operators using BGP sessions, or as your Border or Core Network, and you won't regret it.