Babylock Ellegante has everything you will need – USB compatibility, auto trim, auto threading, large hoop and is very user friendly.
Embird seems to be the most popular software in that it is user friendly and you can begin with the base unit and add to it as you have the need. Visit the the sites for Embird & Babylock.
Dealers will try to sell you the brand of software what the mfg of the machines want them to sell. I doubt if many dealers have software support on staff.
Most, if not all software can format designs for most brands of embroidery machine.