I'm assuming you're talking about yourself, working for another company? The first thing to consider is that a "1099" is NOT an employee, rather an "independent contractor". The IRS takes it seriously when a company claims 1099 contractors, when in fact, these contractors are treated as employees (the IRS wants payroll tax and will fine companies that miscategorize). To be a 1099 contractor, rather than an employee (W-2), you must have complete control over your schedule - when you work, how much ect. There are other criteria, but this is the main one - you must clearly not be treated the same as an employee. The other thing to consider is that if you are a 1099 contractor, you are responsible for paying and submitting your own income tax and self employment tax to the state and the IRS.

It is more advantageous for a company to pay you as a 1099 contractor as they save paying employer portion of payroll taxes. Also you will not count as an employee for the Affordable Care Act (which impacts companies with over 50 employees).

Hope this helps.
Kathryn