I realized how much work Gusto saved me when I had to go file nanny taxes on my own. I actually wrote in and asked if you had a nanny plugin yet (sadly, no, but you pointed me to an overpriced competitor that had it).
I find Gusto is great for the payroll side of things, and Quickbooks online is decent for the bookkeeping side of things. I went through every accounting package out there, I wanted to use a competitor.. but quickbooks was just a bit easier. They do have a payroll piece, but I have not tried it due to liking Gusto. It syncs fine with Gusto.
Taken together the combo is under 100 bucks a month. Not sure the exact scale level, but I think they should work for 2 employees up to maybe 50 employees. I have no idea past that, and at some point I would imagine you need some kind of HR department and a real bookkeeper.. but I can at least vouch for the combo for early employees.
Then for actual tax time, I just found a local CPA that came recommended. He doesn't like gusto, but he likes quickbooks.. so I can just share my quickbooks accounts and he can do his stuff.