Bests & Worsts Reviews from Amazon

I bought the Brother XL-3750 based on the 4-star rating at Amazon and was thrilled when it showed up. My first attempts at sewing produced stitches that were so-so, which surprised me since it should have been basically fine right out of the box. I was attempting to make something for an upcoming craft fair and no way would the sewing pass muster and sell, so I adjusted the tension knob. As others have written, it did absolutely nothing. Actually, with each tweak the stitching got worse. I couldn't even backtrack and set it the way it had been. I tried for 4 hours to get anything that was even remotely passable with no luck. I was tired, frustrated, and on the verge of tears. I called Brother first thing this morning and they insisted I must have threaded the machine wrong or put the bobbin in backwards. They were really no help. They wouldn't cover the machine under warranty even though it was brand new because all I had was an online e-mail verification (no receipt came in the box). I then called their closest authorized dealership just to see if they had run into the problem with this particular machine because, as I now discovered, there were so many negative comments about tension problems all over the internet. They told me to come on down, looking at it was free. I made the 12 mile trip and they fixed the machine in 5 minutes, no charge. Their fix: they took the plate off and popped out the bobbin case, dusted underneath it, then popped it back in properly, tightened everything up and voila! the blasted thing sewed beautifully. Apparently, Brother is now making some lower end inexpensive machines that are sold on Amazon, on eBay, and in places like Wal-Mart, which may work great IF they work, but they aren't taking the same care to make sure they go out tuned up and ready to sew. Hence the reason why some people love the machine and others say it doesn't work at all. Consistency leaving the factory is a problem, I guess. I have no idea how long this fix will work--hopefully forever--but as of this moment the darn thing sews fine. So if you are one of the unlucky ones who gets a Brother XL-3750 that has what seems to be major tension problems and the tension knob isn't doing a blasted thing, please look into taking the bobbin case out--not the bobbin, but the bobbin case--and make sure it's clean underneath and that it sits properly in its spot. They made me look at how it's positioned, but please refer to a manual/diagram to see. They said mine was wedged in improperly and there was a good amount of dust underneath. If this is such an easy fix I'm surprised Brother doesn't acknowledge it or even suggest or recommend you look into an improperly seated bobbin case. Good luck, I hope this helps all those who are as frustrated as I was. I'm giving this a one star review because no one should have to go through so much trouble to make a brand new out of the box machine work.