I've pieced many pieces of batting together with the batting tape and I agree ... it is not noticeable once quilted.

I often piece my batting, especially for smaller projects. I used to zigzag the edges together...until I discovered spray basting. Now I merely lay out my pieces and spray baste both sides. I used a combination of decorative stitches and FMQ'ing and haven't had any problems at all with the finished piece. Found a great rolling storage piece from Ikea with shelf dividers. I went thru all my pieces, rolled them up and sorted according to size. It has helped me to use the smaller pieces since they are accessible. I really hate to cut up big pieces of batting.

It was only recently that I learned about piecing batting with either a zig zag stitch or using a binding method.
I have don't this with a lap quilt and it worked perfectly. Maximize the resources that I have to work with.

I piece my batting all the time. I think it's sinful to waste things and it makes me feel good to use something that would otherwise be discarded.

I also use strips of inexpensive iron on interfacing. Easy, quick, and economical. I can't tell where it is joined.

I save all my batting scraps and piece it all the time and the quilter has never said anything to me. I hate to waste fabric, thread, anything sewing.

I, too, purchased a roll of Natural warm batting and since most of my quilts are queen size, I have not had too much waste. When I do have to cut a piece off, the sizes are great for table runners and potholders.

I have always pieced my batting, with a hand zig-zag stitch or batting tape, and now with 2" strips of fusible interfacing - which works really well. I've never thought that you shouldn't... why on earth not? When the quilt is finished, it is impossible to notice the joins.

Here batting is only available by the meter, so we have to cut it to the size we need. When I have a bag of small scraps, I use it as stuffing for a cat mattress...

Would it be a problem do you think, if you pieced together different brands of batting in the same quilt or are you all using the same brand together?

All the time. I never waste a scrap and no one can tell when the project is completed.