Ventajas
Good consulting opportunities all throughout USA. They have a techie group in Whatsapp that sometimes may help you technically if you need support. As the company grows, they're slowly ramping up their internal site for employee services. Earlier, all requests were through email such as timesheets, general queries. Transparent HR, payroll and timesheet departments. Pays through direct deposit. No surprise salary hold. Management will not have issues with your leave plans as long as you retain your position at client place.
Desventajas
Less transparent and less communicating immigration department. Often you will need to follow up with them quite frequently. If you don't retain your position at a client place, IIS will issue a termination order as soon as they receive end of project notification from their client with a 2 weeks notice period. Sometimes it is 4. Either way, you need to be ready to whatever comes.