What is your reason for just one machine?
All quilters need a back up machine. I won't tote my heavy Bernina machine to class or workshops so I have a portable Janome machine for that. I have a Featherweight because it's awesome and sews great and I wanted one I could leave for my granddaughter. I have a Singer 301 because it's great for fmqing small quilts. I have a Brother 1500 because I won it. I have a Singer Quantum I bought before I started quilting for the decorative stitches for clothes. I have a Singer 15-90 in wood cabinet because it's perfect for paper piecing. I use them all.