A few comments based on my experience with using these products:
C4 Trim Restorer - my favorite product for trim, application/removal is a breeze and leaves an even satin finish. As far as durability I applied to a customer car back in November and it it is showing no signs of fading on a vehicle outside 24/7. Highly recommend.
C5 Wheel Armor - application was simple, I apply and removed one wheel at a time. Finished look leaves a nice gloss and has done a great job repelling brake dust and road film. Cleaning what little accumulation ends up on the wheels is made a whole lot easier.
C2 Liquid Crystal - I dilute to 5% product/95% distilled water as instructed. Application is easy, I began using it immediately after drying from washes and then tried it as a drying aid both with great results. On a black car I did not experience any streaking of product regardless of the amount of product used, same on glass surfaces. Finished look it leaves is high gloss and slick to the touch. I need to experiment with this product more but my overall impressions have been very good so far.
G1/G2 Glass Coating - not sure if this should even be mentioned as these products appear to have been supplanted by G3. This product combo garners a lukewarm review from me, the application of two products (apply G1, wait 15 min, apply G2 over it, remove) is time consuming and the removal was very difficult. Product performance was no more noteworthy than RainX or Aquapel. My experience with this product is limited, so I will be using more often as the weather warms up.