I agree with sleepywombat - it depends on the teacher/school.
I teach English, which is a subject with a notoriously high level of marking. It's complicated somewhat at the moment by the fact that I'm teaching GCSE for the first time this year (previously taught another system) and I'm having to learn and prepare resources for both the old GCSE course and the new GCSE course which started this year. I'm hoping my workload will be lighter next year when things are a bit more settled.
I work very hard and I do worry a lot about my pupils. I often wake up suddenly in the middle of the night thinking "I FORGOT TO PHONE ELLA'S MUM!" or "CHRIS STILL HASN'T HANDED IN HIS LITERATURE COURSEWORK!" and I have lots of horrible dreams about losing coursework/missing deadlines etc. Targets are horrible things, and although other professions no doubt have similar target setting, I don't know if they engender the same emotional investment as ours. If my kids fail then they don't get into college. I also worry about more personal things, like what I'm sending some of my kids home to and what they're getting up to during the holidays. Not much I can do about it, but I suppose I'm just the type of person who thinks about these things.
However, someone earlier mentioned teachers who are 'martyrs to the cause' and I kind of recognise this. My holy grail is to develop a system that maximises my own efficiency, so that I can minimise my workload whilst at the same time enabling all the kids to progress at the rate they should. I'm looking into lots of ways to do this (ironically my progress has been hampered somewhat by a lack of time!) but many teachers don't seem interested in doing the same thing and I often wonder why they prefer to grumble and work ridiculous hours for small gains when they could be devising systems that benefit everyone.
It's always going to be a huge workload and, like all of the public sector, we're underfunded, and this means we inevitably get stretched. If that wasn't the case it would be the best job in the world and I can only imagine what spectacular resources I could create and lessons I could deliver :) But I think it's important not to let it take over your whole life - I have at least one day every week where I do no work at all (unless I want to - sometimes I quite enjoy fiddling with resources and websites, or reading articles and so on. It's a bit of a hobby too, I suppose).
I don't have any basis for comparison because teaching is my first 'proper' job, but I have lots of teaching friends who have come from other sectors, including banking and finance, IT, sales etc. They have all expressed shock at their workloads and stress levels.
This is long and rambly and I apologise for that. It's very late (early?) and I can't sleep. But to conclude: teaching = good, but more hours in the day needed please.