I have to really struggle to keep my seams at 1/4" as I sew. Is it my machine ( Brother) or is it me? Help!

Mine does that too and this is my conclusion on the reason.
By the time I sew all the way down, by the time I get almost to the end, I release the pressure of my hands onto the quilt and I know that it is because I am right at the end and glad that strip is finished especially if its a long strip. When I would hold the same amount of pressure, It didn't go to the right.

Guess I knew it was me causing it to slip away... but I was hoping to blame it on the feeder...

This can be caused by the machine. It just requires an adjustment of the feed dogs.

To test if it's the machine, take a large scrap of fabric and sew without your hands guiding the fabric. If it pulls to one side and starts making a large circle, the feed dogs are not feeding the fabric correctly. A good tech should be able to make the adjustment for even feeding.

You are right! It just keeps feeding more and more to the side... Thanks so very much for your suggestion. Now I'll find someone to make the adjustment for me. I feel so much better now!

Well, now I've located an authorized service center for Brother sewing machines. The nearest one is only 32 miles away, so I'll call tomorrow and tell them my problem. Hopefully they can fix it quickly! I only have the one machine and I NEED to be piecing quilt tops!

Well, first see if the feed dogs are packed with lint. Take off the throat plate and vacuum (preferably) or brush it out. Also run it with the plate off (no thread or fabric) and see if the movement is obviously off. All my machines run pretty straight, even the budget-priced Brother. I had a 1990's Singer which behaved as you are describing. I thought my frustrations were my fault until I finally upgraded!

Sometimes, I find that I have the same problem. It turns out that I am not sitting square and centered to the needle. When I readjust my chair, the seam is right where it needs to be.