I work as a speech pathologist in the school system in Vic. In NSW, I believe the education department doesn't actually employ speech pathologists (unlike other states) - instead Community Health Centre-employed speech pathologists service school-aged children.
A lot of the work a speech pathologist does in schools is with oral language (comprehension and use of vocabulary, grammar, sentences) and phonological awareness (awareness of speech sounds and syllables in spoken words - which relates to reading and spelling). It is common also to work with students with articulation (pronunciation) disorders, and you also see a small number of children who stutter. You're likely also to see a small number of students with autism or Asperger's syndrome. The work involves performing assessments, screenings (e.g. of Prep students), providing therapy (individual and group), and consulting (e.g. devising a program for an integration aide or parent to follow-up with, rather than delivering therapy yourself). You may also be involved with providing professional development to teachers and/or integration staff occasionally. Admin (mainly involving report writing and writing case notes in files) also takes up a good chunk of time - probably 20% or more. In a mainstream (i.e. non-special) school, the bulk of the children you work with have disorders specific to speech and/or language (i.e. not related to low intelligence, hearing impairment, ESL, etc.). The focus tends to be more on the younger grade levels, although you may also work with a smaller number of older students. Secondary schools usually don't receive direct therapy services. Providing assessments/reports for integration funding applications (e.g. for severe language disorder, or autism) is another area involved.
The advantages of working in the school system, from my point of view, are - the children are at least used to sitting at a table to do work (vs. a preschool kid who you may spend half of the session trying to get them to comply with what you want them to do), you deliver therapy in a more natural setting for the child (vs. in a clinic), teachers/integration aides are on hand, and (probably the best one) you don't have to come in to work during the school holidays.
The disadvantages of working the school system are - it tends to pay less well than jobs in the health/medical setting, only a minority of parents are willing/able to attend therapy sessions or do follow-up practice at home (so in a large number of cases, the only therapy the child gets is when they see you, averaging once a week/fortnight), there tend to always be massive caseloads (20-30+ kids per school is not uncommon) where you can't effectively service/see every child who needs therapy and have to make do with a less than optimal amount of therapy. Also, the career structure (at least in Victoria) is often poorly structured and uneven (i.e. I know of a new graduate who landed a position with a higher salary than some speech pathologists who have been practising for 5 years), with limited opportunities for advancement/more senior positions. It's not uncommon to reach the top of what you can earn in this setting less than 10 years in.
The pay in the school system (at least in Victoria) is roughly even/slightly less than a teacher's salary. In Vic, the entry range is roughly $45k-$62k (whereas teachers here start on $51k), with senior/team leader positions in the vicinity of $63k-71k. I believe it's similar in Queensland.
As for liking/hating the profession, I have a love/hate relationship with it myself. It's a pretty good job in the sense that you can be fairly autonomous, work with clients individually or in small groups, get paid for playing games with kids much of the day, and can sometimes make a real difference. It's an interesting area that most people don't know a lot about. The downsides for me are - often you don't make substantial progress with the kids you see (largely with the language-disordered/learning difficulties ones), there often isn't enough follow-up outside of therapy sessions for the student to make optimal progress, the caseload size often makes it impossible to be as effective as you could be (i.e. if you could see a kid 3 times a week vs. once a fortnight), and you're expected to be an expert in a lot of different areas and it's hard to master them all.
I studied at La Trobe (the only uni offering the course in Vic) and can't comment on other unis. Whilst I found the course interesting, a downside I would say is that a lot of time was spent on subjects that have little to do with what you actually practice, and not enough time was spent on learning therapy techniques and other things that are actually useful to know on the job. In the course you have to learn about the whole scope of speech pathology practice - both adult and child. An area studied within this is swallowing disorders - most people have never heard that a speech pathologist manages this.
