I've been trying to find out the exact same things regarding Hatch vs their commercial level E4 series; specifically the designer software.
In doing some research, I received this email from a trusted source:
"Hatch and and E4 are completely different programs. If you are just starting out and you are comfortable with Hatch, I would stick with that as you will be able to learn more about digitizing as time goes on. E4 is a complicated program - the biggest difference between the two would be that E4 has the ability to change everything - so if you are comfortable with high detail work in embroidery such as stitch length, small stitches, stitch width and some formulas to get precision work at an advanced commercial level. Most people get frustrated quickly if they start out with E4 - and as you have seen, there is not much E4 help out there.
I would also like to point out that there is hardly no education for the E4 commercial levels, and if you can manage to find some formal lessons, they are also very very expensive.
The big similarity between the two programs is that they are both using the same powerful stitch processor - so they both have the same stitch processing power, which is awesome.
Unless you are doing digitizing at a commercial level, i think you may benefit more from being comfy within Hatch, learning about digitizing and continue to do classes and keep learning as much as you can. You can always go to the commercial level when you feel its necessary, but Hatch will work well with any business, and will do what you need on a daily basis."
Hope this helps.