Intuit Online Payroll (discontinued)

Because of all the reasons I mention, I would not even choose "1" on the scale of "how likely are you to recommend IOP to a colleague". I would not and do not recommend them anymore. And in fact, when I was speaking to a client of mine today, they stated that "Quickbooks S!*#s" and I agreed. Across the board this company is failing miserably with their customers.

Intuit Payroll is great for companies who want a full-service payroll- filing taxes included

Intuit Payroll is great for small businesses needing to have a fairly hands-free approach to payroll. If you are an accountant managing multiple clients, it is simple enough and the price point is tolerable. You do have the option for the clients to pay the subscription as well. As I mentioned earlier, the roaming employees pose the only major challenge for Intuit Payroll. If you have employees that cross into multiple jurisdictions in one pay period (or frequently), Intuit Payroll will likely not be right for you.

I've only used Intuit for one company, but It worked really well in maintaining different payroll schedules. We have hourly employees and salaries employees and process these payrolls on different pay schedules.

I believe the ideal scenario is when you are already using the Intuit family of products and the payroll bolts on to your existing QuickBooks infrastructure. Payroll software products have been around a long time, and this is a very competitive niche. Most of the companies do a good job of filing taxes promptly, reporting W-2 items properly, providing good reports, etc. Where you might really get some extra efficiency and benefit is the fact that the payroll is woven into the accounting system, creating one seamless enterprise solution. Also, where it might be less appropriate is in a really simple use case such as a one person company where there aren't complex fringe benefits to deal with. In that scenario, you can set up the ACH debits directly with the state agency and the IRS and possibly file your own 941, 940, W-2/W-3 and state equivalent forms. Of course, if you're willing to do this and are good with details, you can save yourself some money.

Intuit Payroll is perfect for the 2 to 20 employee company that is running QuickBooks and is willing to keep payroll in-house. Contractors and professional service companies can keep true job costing in-house and inside the accounting system, which is key to accurate reporting. It's also perfect for any shop with salary-only employees, since that kind of payroll is dead simple.
But its not a "simplistic" tool -- It will handle all kinds of deductions, including 401ks and health insurance. And since its integrated to QB, you get the proper costing of those items without even trying. (Other providers make you import a GL file that creates a journal entry -- which may not give you what you expect.
It's not recommend it for a larger company that needs more complete HR solutions -- go to a PEO like TriNet or Insperity instead.
And worst of all, if you are using the QB Desktop connected version, you do not have access to any time-keeping portal, so all employees must submit their timecards manually (Or have a QB User set up to allow them to punch directly into QuickBooks), which is a less-than-ideal situation for a larger shop.