Finding the right partner is the most important decision you will ever make in your ad career.
Great clients, shitty clients, the economy, mergers, new CMO's, weather, etc. Most things are out of our control but knowing that you get to face all of the weirdness and uncertainly and stress with someone you can count on to hold up their end or even carry the full load sometimes is a small miracle in a crazy industry.
I am reminded of this because I just spent a few days in Mexico with my partner in the ad world for most of my career, Rick Carpenter. It has been my great fortune that he was my first partner in the business back in 1980 and that we worked together for many more years after that. They were the most productive and enjoyable days I've had in advertising.
So don't think as much about what agency you're going to or what client you're working on or how much they want to pay you. Take a good hard look at who you're going to be working with and then make your decision.
I wish you half the luck I had.