Pros
Well respected company, you can expect clients will treat you fairly according to your contract. In 5+ years working part to full time with G&R I was never put in an uncomfortable situations or unprofessional event setting. I always knew I would be paid, unlike many other talent contracting companies I've worked for that are not so reliable. The pay is good in relation to other promotional jobs, you will never see low paying low budget event jobs with G&R. Its a great foot in the door to the industry and pros of the jobs you can get definitely outweigh the cons!
Kontras
In regards to auto shows, competitive companies value team work and emphasize building relationships with their employees while G&R can sometimes make you feel undervalued and replaceable. Other companies that staff for the auto show also pay much more than G&R and often have more perks with pay and travel and do things to keep veterans around. G&R is more of a level playing field, not much benefit to stay as a veteran in MOST cases, there are a couple of exceptions but don't expect to be one of them!