Solar Thermal systems fall into 2 types, Evacuated Tube and Flat Panel. Both types are very efficient at collecting the energy from the sun and converting it to heated water. A Solar Thermal installation can typically have a system efficiency in the 60% range of the energy falling on the panels. Solar PV panels have a system efficiency of around 10% (total suns energy to AC electricity).
The Evacuated tube system is variable in size in that you can specify manifolds with between 10 and 30 tubes, so different size arrays can be designed to fit the most complicated of spaces. The flat panel system looks very elegant when roof integrated.