I have the Brother SE270D which is an older one- and LOVE it- it does not connect to the computer ,so can't answer that for you - but can tell you it is pretty simple to use :lol: I have yet to use it as a regular sewing machine - as I have other machines for that.
Are you planning on using it just for embroidery ? If so doesn't the second machine have a bigger hoop area ? The 400 is a 4x4- if you "just" want it to embroider- and the other one has a bigger hoop I would get that one :wink: