Gusto is a great payroll option and they have recently added benefits. Right now benefits are only available in California.
Another option to consider is Zenefits, which started out as an HR software and benefits provider and added payroll in 2015. They cover all 50 states for benefits.
If you're looking for a PEO (professional employer organization), check out Justworks. TriNet is also a good choice. PEOs are more expensive that payroll providers, but often it is worth the extra expense for the security of knowing that they are the employer of record and handle all compliance.