I have really enjoyed the Sirius Extreme, so it has earned my positive writing. It's very lightweight for a 4-season tent yet could hold three people in a pinch, plenty of room for gear. It ventilates well in the snow and is certainly waterproof. The waterproofing (and windproofing) was well tested during a harsh 10,300ft altitude Utah late summer storm which began with a couple hours of downpour rain so as the tent sat in a 3 inch deep puddle ( no I didn't set up in a rain basin). Contrary to my nervous expectations the water which the tent sat in (3 inches submerged) never entered inside, nor did water collect inside due to condensation. The rain eventually turned to sleet and sleet to snow with a beautiful 8 inch snow blanket covering the landscape by morning. I like the way the tent sets up with an innovative pole sleeve design that allows one to set up while wearing gloves. Quick tightening devices are also included on the guy-lines, thus it's unnecesary to tie them in the cold, another innovative plus. Winter camping with two (total) keeps the interior moderately warm, especially if the edges of the tent are lined with snow as to seal the gap between ground and tent. The vestibule is large enough for a couple large backpacks, though if only sleeping two, there's plenty of room for gear inside as well. Due to this tent's very packable weight and big comfort it will replace my 3-season Big Agnes SL2 and REI Hallfdome 2 for any excursion with storms in the forecast.