All of the photovoltaic solar panels / solar panels we stock and sell are manufactured by large reputable companies who are major players in the solar power industry. As such, you can rest assured that they will still be around in years to come to support their products and warranties should the need arise.
Monocrystalline vs Polycrystalline Solar Panels
There seem to be lot of confusion between the quality lifetime and efficiency between the various types of Solar panels. Salesman likes to quote advantageous and disadvantageous of each in order to sell the preferred option.
Monocrystalline Solar Panels get the name from “Mono” Single crystal, each cell in a Mono crystalline is created from a single crystal growth, thus the panel is made up of “matched” single crystal and when the panel is manufactured all crystals are lined up in the same direction , so they appear darker by color. The advantage of a Mono Panel is that the PEAK performance of a single panel is generally higher because all crystals are focused in the same direction
Poly Crystalline Solar Panels get the name from the “poly” or multiple crystals; a Poly is made by cutting the various crystals and combining a unit from various pieces/cut offs etc. As a result there is more interconnections in the panels and the crystals are not focused in the same direction, so the PEAK power is often a bit lower than that of a Mono, However this so called “deficiency “create an advantage in other ways as the crystals are somewhat scattered in all directions, the solar panels is more prune to generate electricity “earlier” and also more over a widespread of Sun Angles
As Synopses, if you would compare to solar panels a Mono and Poly but placing them right next to each other on the same roof and monitor the harvesting over a year the performance will be within a few percentage points of each other. At the end of the day the STC (standard testing conditions) for writing the specifications of the panels remain the same, thus a 250W Mono should deliver the same as a 250W poly. There would rather be a bigger difference between the range of Poly or Mono if you compare different manufacturers of the same product , then between the 2 types of panels.
Mono, Poly and Thin File Panels

It is thus more important to concern yourself with the quality of supplier or manufacturer of the solar panels and the history of the manufacturer as well as your local supplier than it is to concern yourself about the difference between the type of panels.