Thanks for the replies - I read the following on Betterment, and wonder if in your experience the amount of work for the 401k is greater and or more confusing than the SEP.
You might be wondering why anyone would do anything but the Solo 401(k).
Here is why: First, setting up an individual 401(k) typically requires more advance planning and paperwork than opening a SEP or SIMPLE IRA (either can usually be done online in just a few minutes). In addition, individual 401(k) plans require you to file Form 5500-EZ with the IRS every year once the plan reaches $250,000 in assets. And of course, with the solo 401(k) you have to be your own company with no employees.
Also - If you knew now that in 3 years she would hire an employee, how might that affect the choice?
Thanks