One thing to consider is that silnylon will absorb water, even if doesn't leak. Then it stretches and sags and needs occasional tightening. Silpoly repels water so that's not a problem.
Very true about SilNylon.
On a five day swamp hunting trip in Blackwater WMA using my Gheenoe boat.
''One night'' > 1, of constant rain and my new'ish henry shires contrail tent was sagging onto my sleeping bags, [WM mity lite/MLD bag/blanket on top].
When the rain slowed I put my Equinox poncho/shelter over it, put the bags inside Equinox bivy, both SilNylon. By the end of day two all three were soaked through. The synthetic MLD blanket with Event material did a pretty good job of keeping the down bag dry, enough so that I toughed it out, a bit soggy.
I tightened the tarptent just enough to try and get by, then some high winds blew in and damaged the tie-outs, etc..
I sent the tent back to HS Tarptent and emailed them pictures. Their ''policy'' was if something happened and the tent was not abused, they would repair it for free. They charged me for everything shipping/repair/return shipping. TarpTent is no longer a company I would buy from.
Just about anywhere can get rain/wet snow conditions keep that in mind with silnylon products.
I've been looking over everything I can find 'the perfect' super light weight drop and flop for a night or two, >dizzy'ing I tell ya.
Over.