I have a Hoop-It-All and I like it fine. I am currently making a Christmas pillow that will be about 12" square using the HIA. The HIA has several hoops and I have them all....about 12" of emb space x 12", 14", 20" or 24". However, the machine will only read a space the size of the Large Oval Hoop, which is a standard hoop. Since you have software, you can "build" a quilted square and then split the design into segments that can be sent to the sewing machine to stitch out. There is a new HIA clip that allows the sewing machine to read and sew designs the size of the Mega Hoop (an optional Bernina hoop). To be honest, I enjoy the HIA for embroidery but would not use it to quilt. It is not a Bernina product so support is a little lacking. Also, it requires a wide sticky backed stabilizer to embroider (or quilt) since the "hoop" is just a square (or rectangle). There is not inner & outer hoop like traditional hoops. If you to quilt using the embroidery module, it might not be the best option.
I do use the Mega Hoop and love it. It's not much wider than the regular Large Oval but it is long and I can rehoop pretty accuratly. It uses less stabilizer than the HIA and I often find it's just less hassle. But again, I use it for embroidery and but not for quilting. However, since you can actually hoop your quilt, it might be possible to avoid stabilizer of any kind for quilted designs.
I have no experience with the Magna Hoop. Hope others can advise.