I bought one in October and love it. I've made 6 quilt top/backs since then. I will tell you I use the walking foot that has the bar on it. I love that it will cut my thread.
I did take it back about 2 weeks ago so they could look at it. At times it wouldn't sew or I should say that it didn't stitch. It was the thread. The service guy that looked at it said that the Aurifil (spelling is wrong) is to slick. At times when using the "scissors" it doesn't go back to the "cut" position.
One thing that they checked before I took it home was the take up arm (I think that is what it is called). The arm that is on the left as you look at the machine. There should be a small black piece on it to hold the thread in place. Apparently some were shipped without it.
My fabric doesn't get chewed up nor slide off from where I'm sewing.
Maybe take it back to where you purchased it to have them check it out and give you some tips.