If I had to pick one, I'd go with the winder. I have both, and knit every day, but I don't only knit with skeins--some are pull balls. However, if you have someone to hold the skein while you wind it, I think that's better than having the swift and winding by hand. You can improvise a swift, but not the winder.
I also just frogged a sweater directly onto the winder and it made life a lot easier!
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry