I have been a freight dog for a couple of months. While the job is exactly what I expected, and I enjoy it, it is uncomfortable enough to where I sure as hell don't want to do this any longer than I have to. I have done UPS runs on IOE and I fly on demand single pilot all over North America. Here are my thoughts on the 2 different areas.
UPS
Schedule sucks ass. Wake up at 4:30, wait for freight to be loaded, fly for 2 hours then unload your own freight. Sit at some crap hole FBO or crew apartment for 10 hours and come back and be home by 9:30-10:00. Just in time to eat dinner and go to bed. UPS rampers giving you crap because you had a headwind or ATC delay when you get back. Flying to the same airport everyday sucks, IMO, but there are those who like it. There are a lot of lifers/long-termers at my company, and I don't know how they do it with families. Some are outstation based, so they spend nights away from home and sit for 10 hours at home during the day. Neither are really ideal. Pay at my company for these routes are good, but for me, my goals and aspirations are bigger, as far as pay goes. This doesn't suit me at all.
On Demand
No real schedule to speak of. This week, I flew M-W and had no trips on Thursday or Friday, and had the weekend scheduled off. Although I wasn't "off" on Thursday or Friday, I was able to get a lot of rest in and get some errands/honey do's done around the house. The previous 2 weeks, I worked a ton. 16 hour duty days with 5+ hours of flying is really fatiguing, especially when we only get minimum rest after a 16 hour duty day. I have spent a few days in hotels, but not a lot, as we usually come back home after a trip, depending on duty/flight time restrictions and bids on new trips. Most of the time during the week, I see my wife at 5am when she is getting ready for work, or not at all. It is feast or famine. I kind of enjoy the random chaos, it keeps things interesting.
This isn't a total bitchfest. Like I said, I enjoy the job, but it isn't all sunshine and lollipops. I get paid a respectable wage, I don't take any headaches home with me, and I enjoy the randomness of the on demand world. I don't really enjoy pushing around pallets, but it's part of the job and I knew it going in. Flying the metro has been fun, although it would be nice to have an autopilot. There is something to be said about being your own boss with very little interaction with management. We don't have any management at our on demand base, and we do our own flight planning, weight and balance, and performance figures. Our management backs us up when we make a PIC decision.
If you get on a with a good company, it can be a good place to hang your hat for a while or make a career of it. For me, I am looking to put in a couple of years and move on. Others have stayed put and enjoy it. To each his own.