Hi, Bernice.
Brother is a very good brand and is very user friendly.
Models ending with the letter D are Disney machines and have Disney designs built in.
Other models do not have these designs, nor can you load these designs to any other brand or model of Brother.
You did not indicate you were interested in Disney, but it was mentioned by someone without any explanation.
Make a list of the things you would like in the way of bells and whistles.
Opt for an embroidery area of at least 5 x 7. A lesser area will limit the size of the design you can stitch out.
Visit as many dealers as you can to test the different models.
Babylock is another brand in the Brother family. They usually are a little more expensive.
There are Futura groups on Yahoo should you decide to keep the Singer.
Best wishes.
PJ