My experience of portage was absolutely great, but I guess like most things it is down to the individual. We had it once every two weeks for 1h, from jan-aug. First time she brought a few things to see what level ds was, then planned sessions round that. She had a visual board on velro so he knew what was coming and she always organised 6 activities for up to 50mins, last 10mins writing up sessions. For example one game, a large wooden chair, she gave ds a dog and said 'under chair', initially he did not understand, but she took his hand and placed it under the chair, then over again with other items, over, in front etc for a few items, following week it was a house, and ds put object under the house - it was wonderful to see. She did colours (to begin with matching colour object to correct coloured card), numbers, jigsaws, threading, role playing - set up a park scene with duplo, see if he could put a girl on the swing etc, by the end of time with her, memory games, taking turn games, rolling balls to each other.
He loved the sessions and would run to the door when he heard it knock shouting her name and drag her to the table we set up for them to work at. So by the time she left, he was a much more confident boy, learnt to concentrate, answer 'what' questions. She had amazing patience and when he had a tanturm and throw things around, she manage without really doing anything to calm him down and he picked up the objects he threw and they carried on. The tantrums decreased. He was not really talking when she started and I'm certain she help bring that on.
She also always spoke to me and we discuss things that might work or not - and would find info out, and came up with suggestions which was lovely. Also gave us pecs card for daily activities eg. toilet, teeth cleaning etc, but we could give them back when she left as he fine with that now.
sorry bit lengthly, but to me it was fab, and we both really miss it now. Now he knows his colours, numbers, taking turns, sharing and answering qus - well sometimes. The main thing they tailor it to the child not to the condition.