In fact, ADP is one of the world's largest providers of outsourced business solutions. Revenues are nearly $8 billion per year.

In the world of payroll outsourcing, ADP is known as a traditional payroll service or a conventional payroll service.

That's in contrast to the newer generation of payroll services such as SurePayroll that offer an online payroll service.

Online payroll offers the added advantages of control, visibility and reduced errors, typically at lower payroll service prices than the traditional big boys: ADP and PayChex.

Nonetheless, markets get wise slowly. ADP continues to dominate the payroll industry with massive market share.

After all, ADP is a well-established brand and you can "never get fired for choosing ADP" as your payroll service. The boss will know the name.

It's a bit like the saying "You can't get fired for hiring IBM" -- a saying that used to hold true. These days, you can indeed get fired for hiring IBM as their are plenty of other good technology providers out there and there's a lot at stake.

Something similiar is going on in the payroll processing industry. What once was a near monopoly by ADP and PayChex is now a much more competitive marketplace. So, we recommend that you evaluate ADP payroll outsourcing but also evaluate SurePayroll and PayChex to get a good comparison. To our mind, those are the three full-service payroll providers worth talking to.

On their website, ADP says they provide "flexible corporate payroll services that improve payroll management for employers of every size. We handle the time-consuming tasks of payroll processing and employee payroll tax filing so employers — regardless of their size — can focus on their business."

While they seem adamant that they can handle any size business, ADP's sweet spot is with large businesses having 500 or more employees.

To us, ADP's biggest advantage is that they are used to working with big companies that have very complex payroll processing needs. If you run a large company, you won't find much that ADP can't do for you.

For a small business owner, however, that complexity leads to feature overkill and confusion.

Because ADP's offerings have been developed over so many years, there's an inherent legacy complexity that they seem to have struggled to overcome.

Even as ADP adapts into the Internet era, it's tough to figure out what they are doing.

They launched an online payroll application called RUN ADP some time ago but now if you go to those web pages, there are some allusions to RUN ADP but most of the language is about EasyPay.

Unfortunately, big companies tend to start and stop entire business units on short notice, so I'm not sure what's really going on.

Ages ago, I was a Peachtree accouting software user and ADP built a decent interface directly into the software. They had in fact acquired Peachtree so it was easy to do the integration. Then, all of a sudden one day, they stopped offering the integration and divested themselves of Peachtree.

OK, I digress but you get the idea. Big companies don't have much empathy for small companies. That's why I personally opted not to use ADP as my payroll service at a certain point. It just didn't seem like they gave a hoot about me and my business.

Of course, that was back when you had to call in payroll on a specific day and time -- which was a pain. If you had an important sales meeting at the same time as payroll needed to be called in, you were in a jam. That's why I now prefer the anytime, anywhere online payroll services, where I can process payroll in my PJs in the middle of the night if I need to.

So, getting back to this review of ADP payroll service, we haven't had a chance to put RUN ADP through the paces.

ADP tells us via their site that RUN is easy to sign up and set up, easy to learn and use.

Step-by-step wizards help you set up company and employee information to get you started. You can calculate and generate paychecks on an "as needed" basis, and pay employees through direct deposit or by printed checks.

Just like with SurePayroll and PayCycle, you can set up automated reminders on payroll and tax due dates, so you minimize the risk of missing a deadline or paying a late penalty.

So what are the drawbacks?

The knocks again RUN ADP are that there is no electronic filing at the state level, and the business owner must file all tax forms. Plus, there are no weekend support hours.

To our mind, these are some big disadvantages, enough to make us shy to recommend this relatively new offering.

Our part-time bookkeeper uses ADP for some clients and uses SurePayroll for others. She is not keen on ADP's payroll service limitations.

As an example of her frustration, she says that SurePayroll automatically does the 1096 forms for her, whereas ADP does not do the 1096 form for her. She has to do it herself. She says that's a big pain.

She also likes SurePayroll's instant payroll preview function much better than the way ADP informs her of the amount she needs for a payroll. With SurePayroll she gets the grand total for payroll instantly. With ADP, shes says she processes payroll and then gets an email 5 hours later telling her the required cash amount.

Long story short on ADP payroll outsourcing, don't go with them just because they are massive. Shop around. Talk to other players and get a payroll service that is right for you. Once you choose a payroll service, it's a pain to change so ask tough questions and don't move too quickly to decide.