I owned a 2144 and I use an Ambition 1.0 at work so I am familiar with both machines. If you want a basic workhorse machine, Pfaff is the one for you. The Ambition 1.0 is a basic machine with IDT. It has some embroidery and basic stitches as well as some stretch stitches. I am a seamstress in a bridal shop and we use it at work for alterations so it really gets a work out. We have used these machines for several years and have had no problems. The machines are working about 8 hours a day for 4 to 5 days a week. The 2144 is a great machine as well. It also has IDT. There are many built in stitches to do a wide variety of sewing, quilting or what every you want to do. It also is an embroidery machine. I have done some beautiful embroidery on it. You can download designs and stitch them out or stitch out the built in designs.
You said you wanted a piecing machine. Either one will be perfect. It just depends on how much you want to add embroidery to your sewing or not. Both are great machines and will be very dependable for you. I know I sound like an ad for Pfaff but I have owned a Pfaff machine for over 25 years.
I traded my 2144 for a Creative Sensation Pro and I love that one too. Someone mentioned price and Pfaff may be a bit more expensive.......you get what you pay for. I am a 'Pfaff girl" for sure.