I did 10.5 years active before being hired by a major but I made it a priority to get a RESERVE job. The reserve job was a savior to the instability of an airline career. A good friend stayed in the military full time. I would say the major negatives about active duty are moving, fitreps, next set of orders, deadlines, politics, and deployments however you are probably home more consistently and job security is great. The negatives to the airlines are job insecurity, initial pay, time away from home, and randomness of personalities however you take no work home and most negatives change with seniority. My buddy wonders all the time about the same decision and I tell him the trick is finding the job that you gain seniority the fastest but also allows for good pay and security. I was pretty active in the reserve world and was mobilized for 2.5 years during my furloughs but I am now reserve retired have really enjoy the time off with the airlines.