I discovered the wonders of a cot about 2 years ago. I backpack a lot in CO mountains as well and have never slept well at night on a thermarest (tried all kinds - flat, tube style, etc). However, I am a side sleeper and no matter how thick my thermarest was, I always found my hips were hitting the group a bit when I slept on my side and hurt (or I had to inflate it so much that felt unnatural). The cot solves that problem as it flexes well. If you sleep just fine on a thermarest, then I suspect you don't need a cot. But if you sleep like crap, a cot is a miracle. I will admit, I never tried a silverback paco, but didn't want to mortgage my house to get a better nights sleep.
As an aside, most folks here are in love with the roll a cot. I'm sure it is fine and the weight is better, but I use the REI made cot. it is steel, so about 7 lbs heavier, but sets up in 30 seconds, vs. several minutes for roll a cot and if you get 20% off sale at REI, costs less than half as much (around $50).