They've helped me quite a bit. I've got a deviated septum and terribly congested sinuses most of the time. It's no cure, but in bed - when all your congestion rolls around your head - they do help keep a reliable airway open and I snore less.
My husband used them, too, until he lost about 75 pounds and no longer needed them. We think it's because he had a touch of sleep apnea and that's what caused the snoring.
I've never tried the nasal strips, but what I use is a Sudafed Plug In, it's brilliant, if you have a plug near where you sleep you plug it in about 1/2 hour before you go to bed and leave it on all night, I wake up cleared headed and breathing freely. I can't recommend it enough.