You will end up devoting your life to the Postal Service - your schedule is owned by them.
Pros
The compensation in income is excellent. Staring at $21.50/hour and most weeks I worked over 40 hours, so the overtime kicks in (time and a half) and shoots your annual salary to somewhere over $50,000.00. If you like outdoor activity - and are in excellent shape and love walking and doing hard physical work, you could end up loving this job.
Cons
I think it all depends on where you live. In Wisconsin the winters are cold and snowy and harsh, and the summers are hot and humid, and the insects devour you, plus as a TE you'll be going constantly - not much time to break for lunch - I ate snacks while walking and driving most of the time. By the end of three years my bodyfat % was around 4% or so - keeps you lean and in shape. You'll end up spending lots of money on clothes also if you live in an environment where it snows or rains a lot. I went through at least 2-3 pairs of shoes a year. They break down quickly, as you're walking anywhere from 3-10 miles/day. As a TE, your schedule will change daily. You'll have no real set start-time or end-time. You can pretty much forget about scheduling or planning any appointments. If you live in a large enough metro-area you can also forget about days off. You'll get one every few weeks or so, but you most likely won't know until the morning of, when you're called at 6 am and told to stay home. The work is 6 days/week even though you're only guaranteed something like 4 hours/day one day/week. In a large enough area, there is ALWAYS work/routes available. It will take a good few months to really get into a rhythm with this job, and you'll end up cursing yourself for taking it for at least the first month or so. After that it gets easier, and you'll start to shed any excess bodyfat and get into good cardio shape very quickly. My legs were like tree trunks after the first year or so - great for the legs and the calves - waistline too. Horrible for building any muscle in the upper body. As a TE forget about it. You'll be thrown onto routes you don't know every day for the first several months, and when you finish you'll be asked to go back out and help the career carriers finish their routes. It's a constant battle of being strategic, not working too slow or too fast. You learn quickly to pace yourself or you'll burn out. The winters (in any northern climate anyway) will test everything inside of you. You'll get so exhausted that you'll become physically ill. But you can't really take any sick days so you'll have to push yourself through this and keep going until you almost literally throw up. Then keep going some more. You'll have to deal with irate customers who will tell you to your face that they wish their regular hadn't called in sick that day, because then they wouldn't have you screwing up their mail and delivery. You'll have to maintain your composure at all times and realize that you're simply a cog in a machine. And make no mistake about it, you are only a cog. Advancement only happens with seniority, and as a TE there is no such thing as seniority. Hiring/promoting only happens on a regional level so your immediate supervisors will have nothing to do with this. But hey, the money's good. And you can eat anything you want outside of work and not gain weight!