I've been in HR for 20 years and when it was time for our start-up ProfHire to hire employees, I went with Gusto (gusto.com
), because I know what a mess it can be if you screw up on taxes, worker's comp, etc. I have been very happy with them. They send reminders of when it is time to do payroll, etc. Gusto used to be ZenPayroll before Zenefit took over the Zen space.
By the way, you really don't need a PEO or an HR firm. (Gusto charges something like $9 a month per employee.)