If your just recreational riding or commuting to work, the more upright position will be best for you. Unless your racing or in a hurry to get from point A to B then you do not need to be bent over which is harder on your neck and arms. Myself, I prefer an inbetween position so I ride a mountain bike frame all built up like a road bike. It is fast and efficient enough and my riding position is very adjustable for comfort on a 1 hour commute or a longer 4 hour weekend ride. The key is to have enough stem height to get those bars up and then your saddle will need to be selected with much care because you will be balancing more of your weight on the seat. The important thing to remember is cushy and padded saddles do not provide more comfort for the long runs. Support is the key. It needs to be firm yet wide enough to support your sit bones and have a short nose. Forget about those comfort bike saddles as they will not give you the support you need because you will just sink into them and chaffing and discomfort will soon develop. Also stay away from road bike and racing type saddles as those are meant for just leaning on while in the aero position and are not designed to support any of your weight.