While it can appear a little daunting at first, a PV system can be broken down into easily understood building blocks as follows:
1) Several PV modules are strung together
2) whose output is accumulated in a combiner box
3) whose output is sent through a DC disconnection switch
4) which is then fed to an AC inverter (that converts the DC to house/grid compatible AC)
5) that is then fed to your house service box (which is already connected to the grid)
Typically, all of these building blocks have UL and NEC compliance and use UL and NEC compliant cables and connectors to bring it all together. Not so complicated, right?
The high cost of crystalline silicon wafers (they make up 40-50% of the cost of a finished module) has led the solar industry to look at cheaper materials to make solar cells from. Thin film technologies use significantly less silicon which reduces initial manufacturing costs. They also use a silicon deposition process that lends itself to very flexible construction which opens up uses in many consumer electronics applications, as well as, may offer particular design advantages for Building Integrated PV (BIPV) applications. Some people prefer the aesthetics of the black thin film modules to better match their black asphalt shingle roofs as well.
Thin film also has some significant disadvantages though. Since they use less silicon, they can produce as much as 50% less power output. That lesser output translates into more up front modules and hardware required and higher long term operating costs through more real estate and roof space required for the system. They have also shown some significant degradation of performance (15-35%) over time versus the crystalline cell modules which also contributes to higher long term operating costs.
With all that said, one of the largest commercial and utility scale module producers in the world, First Solar, uses CdTe thin film in their module designs. https://sunlution.wordpress.com/2012/09/11/top-10-solar-module-manufacturers/