Research Position - lots of pressure, a lot of people cannot take it, many are let go after 3 years, many make it to the 5th year and are denied tenure (if you made it past 3 years, there is a pretty good shot that the department will support you - unless of course something bad happens).
You typically teach 3 courses over the year (2 in fall, 1 in spring) and may have the summer to yourself (you get paid for 9 months, the salary can obviously be distributed over 12). Take the pressure of completing your PhD and multiply it by 10 - probably a good approximation. Oh, make sure your wife or girl friend understands what you are getting into. If you want a research position, work for a rock-star academic and start very very early. You will be absolutely miserable for 4(or more) years, but you won't regret it if you really want a research position.You would have to be very very good at research to survive in a research position. How would you know? - well, if you can publish before graduation, thats one good sign. If you have a detailed plan of how you plan to get tenure, thats another great sign. If your advisor still smiles at you after the proposal defense, thats a really great sign.
Finally, publish or perish is the only model where you are rewarded for your research. If you like research, but have a job in a teaching school, you will not be able to find time for research.
Teaching Position - Less pressure, you typically teach 3 courses per semester or more. relatively laid back and if you enjoy spending time with students, this is for you. A lot of faculty become sick of teaching after a while and I perfectly understand why, especially if you are teaching a core course that not many care about or have to deal with undergraduate students all the time. I am not sure if you are required to do research at all.