Think I'm sticking with alloy or Titanium now from hearing this.
Titanium is a problematic material to work with and at the temperatures used for welding it can absorb Oxygen and Nitrogen which makes it prone to cracking.
The welding of aluminium weakens the surrounding area which is why most bike manufacturers have a posh name for the assembly technique used as they are trying to overcome this issue.
Steel reacts to water badly and weakens over time.
Now to address the statement about UV impacting resin strength, although this is technically correct you must remember that this material is used by aircraft manufacturers, boat manufacturers, motor sports, the medial industry for prosthetics and in the construction of wind turbines and solar panels. The reason that they do this is because of the strength and weight. With a traditional material it is exceptionally difficult to create a down tube from titanium for example which differs in thickness and profile, let alone torsional stiffness... how many are Titanium areo bikes can you name?.. You can change the characteristics of a tube made from a composite material with the lay up.
All materials have good and bad points, but you should not discount any because of a statement made on a forum. The common thing they all have is they are materials suitable for making a bike and if any have manufacturing defects they will fail.
as a matter of interest there is a video on youtube of Santa Cruz testing mountain bikes to breaking point. Not only was carbon frames the strongest but they broke in a manner similar to the alloy frames, they did not explode or shatter