None that are specific to the company. Any cons like a lack of work/life balance come from the nature of working on a political campaign and not from DigiDems itself. Likewise, your job will be different depending on which campaign you're on and the campaign's structure and culture will affect you more than anything DigiDems does. The main con is that since its a campaign job, the position and excellent pay that comes with it, ends at the end of November. They will help you secure post election day employment and as campaigns are always happening may have continuing positions, but don't expect this to be the 9-5 you can retire from in 30 years.
Lastly, as its a temporary (6-3 month) position, there are no benefits. The pay is definitely enough for you to obtain your own healthcare on the open market, but there is no benefits package.