I own Featherlite pants, it is something I pack and carry often when its cooler and/or damper. What's your question? Weight?
I don't use Featherlite pants particularly for waterproofing, I use them as predominantly to add a bit of insulation, summer rain reduced chill on bare legs, to slow the wetting and add a bit of insulation to poly-cotton long pants. I have beefed up the DWR via some Nikwax TX.
I find I cannot really wear waterproof pants, apart from Paramo when its close to freezing temperatures, as simply far too much heat generation and easily becomes sweaty, I'm typically one or two layers less on my legs than upper body. I have some OMM Kamleika pants for winter wet cycling and they just about have enough breathability if its cold and I'm not pushing my output too much.