From mooching around this forum and talking to other foster carers in my area I have pretty much worked out that if you are an LA foster carer:
You will probably never be without a placement as there is such a shortage of foster carers nationally. Social workers (yours and the foster child's) often go off long term sick or change at short notice so you will probably struggle a bit to find any help from social services if the f/child displays any behaviour you feel is unhelpful or dangerous to them (or you/your family). You will probably speak to a different SW each time you phone the LA who probably does not know the child. You will get less money with the LA. You will have to buy all your own equipment and pay for really everything to do with the child as cash in tight and most LA's simply do not have any. There will be little or no help for any mental health issues the child may present with (unless they are kicking off at school). If behaviours are displayed at home and do not involve drugs/sex/alcohol/stealing/running away, you will be expected to deal with them yourself (i.e. bedwetting, anger issues, trashing bedrooms, soiling underwear, watching porn on laptops, selling things you have bought them, internet bullying via Facebook).
If you foster for an independent (or charity) fostering agency:
You will receive around double the amount of money to foster the same age group. You will have a lot more support from your agency, weekly or even daily contact to see how you are getting on, and your SW will be more accessible to you as their case-loads appear to be lighter than the LA's and they tend to stay in their jobs with the IFA's with more stability (and probably more job satisfaction!). There are usually staff employed by IFA's that you can call on to work with the f/children on social skills etc. Mental health services for the foster child are more readily considered and offered through IFA's. You may struggle on occasions to have a placement and may wait many weeks between placements so be prepared to call on your savings in times of no placement. It is thought that the more difficult to place children are placed via independent fostering agencies. Be prepared for a fostered child to be removed and placed back within the LA (to save the LA cost of the IFA) once an LA carer becomes available.
We chose to foster via our LA as we wanted to care for children in our area now that our own have flown the nest.
This was a quick overview of the main facts as I see them and it all sounds a bit harsh so apologies for this. Fostering really is about making a difference to the life of a child who would otherwise not have so many life chances. The foster children are what make it worth while - it is just the difference between the two systems (LA and IFA/charity) that causes the frustrations.