Pros
When I first interviewed with Liaison, they kept saying, "we're not a staffing firm" and I thought "yeah, yeah, whatever" but it really turned out to be true. I've worked with a lot of staffing firms and usually you have little or no connection to them, and have even experienced a lot of problems like them being hard to get a hold of, making mistakes with payroll and being slow to resolve them etc. But Liaison actually feels like your employer. They provide sick leave at PTO which is almost unheard of for contractors, they provide medical insurance, access to training through Lynda.com, they check in to see how things are going, as well as providing activities like a holiday party, happy hours etc.
I really enjoyed the role they placed me in and the pay was good. Were it not for some conflicts in values over the industry I was marketing to, I would still be there today and I continue to refer any friends with a marketing/design background to them.
Cons
At the time I left they had to cut down on the medical benefits due to very high costs the previous year. I think they still paid 100% for the employee but the coverage was not as good. Not sure if that has changed since then.