This 10A MPPT regulator from Chinese firm Juta represents amazing value. Suitable for 12V systems with 12V panels only (up to 125W), the unit intellegently tracks your solar panels' maximum power point to provide 10 - 30% more power to your batteries than you would get from a conventional solar regulator.
Typical efficiency is a remarkable 95-97%, and it comes with plenty of safety features such as reverse polarity protection and overloading protection. It also has an optional low voltage disconnect feature.