Hi and thank you for using Just Answer.
Per your question, there isn't much of a difference outside that ecam 22.320 is a bit more fancy looking and has a couple extra options. The ecam 21.110 is a more simple to operate, and generic looking. Not knowing what your intentions are with these machines, but if you just want the basics, then the ecam 21 would be the way to go because it does basically the same and the ecam 22. however the dial allows you more control. The ecam 22. does it all automatically, and instead of using the dial, you have a control board doing it for you. I guess you can say the ecam 22. is an up grade from the ecam 21. Depending on how this company works, sometimes they'll take the same machine and give it an up grade, ad some more bells and whistles and give it a new model number, and in this case this looks like what they had done. If you have questions, please ask. I wish you the best.