Still waiting on payroll company to fix 4th quarter 941. Technically W2 too, but I was able to file a corrected W2 via Turbotax. "I'm a one person business and I'm telling you the number in box 1 is wrong - just fix it". I even tracked down the re-production steps for their QA (actually simple - re-run a payroll twice that has 401k withholding in it and watch what happens) but they still haven't fixed it for this year and no hope of this being fixed in the software for next year either.
On the plus side, I'm now with a different, local company that will save me over $400 / year ($75 one-time startup, then $8 / month / person. Vs. $40 / month + $6 / month / person - that's gonna add up quickly). They even walked me through one-on-one over the phone everything I need to do with their software, which looks like something I'd have built as a college project ~2003.
*This was Wave Payroll - actually 2nd year in a row with a problem but last year I remember the service being a lot better. New (to me) Local company is payoutusa which is regional - have everything set up for February payroll at the end of month, we'll see how it goes. So if you're in the southeast US, have a fairly small business, and don't mind a pretty much naked HTML form type of website, they might work for you.