Hi Parky,
easy mistake to make!
Ok - so we are both in the dark about factor 3.
Factor 2 eventually goes a bit bobbly on the smooth outer face but my impression is that the insides stay fluffier than a polyester microfleece of similar age. Mine is at least 8 years old and gets used/washed (used perhaps three times before washing) around 10 times per year. It's not often cold enough for me to use it... but ditto the polyester stuff I have of similar vintage.
The reason I keep returning to Factor 1 is its abrasion resistance and durability. I agree that it doesn't dry noticeably faster than polyester baselayer (and certainly isn't as fast to dry as polypropylene). However I climb indoors & outdoors in them and have often used them under rucksack straps. This has taken its toll on my other synthetic baselayers - polyester (Odlo, Patagonia...), Polypropylene (Helly Hansen) - but the yarn and weave of Factor 1 seems to make it far more resistant. I can tell that the whites change colour over time (as I have various vintages to compare) and the fabric gets less supple, but it keeps on doing it's job long after any fibre treatments must have worn off.
Cool T is something that I haven't tested as much as the others. It is certainly less warm than Factor 1 and I reserve it for scorching French summer days. Unfortunately, it clearly isn't as bombproof as Factor1 as I have already got some fibres pulling from a stint on French limestone. However, it saves me using sun cream (which just gets slippery when I sweat) so it comes along for sunny weather belays in the Pyrenees. I have also found that it's less close fitting so carries over into casual a little better than Factor1.
I am not really a 'brand' person, and have cut the external labels off most of my SZ stuff. But I reckon that I wear an item of SZ clothing for sport on average four days a week!
John