Hi mompa 
I went to see both when considering schools for dd1.
They both had pros and cons, for our situation.
Rainbow: like the style of ABA they do. Nice and friendly school. They were in ver small premises att eh time, which meant quite cramped clssrooms. Not sure if they have expanded/moved - we looked at them just over a year ago. Nowhere ot park (would have been a real problem for me as would have been driving dd1, and have toddler dd2 to deal with too - all right on the main road, double yellows with meter bays). Very littel outside space - would have been a huge issue for dd1, as she is a total outdoors girl.
Also, it was just too busy for dd1 - but that is her requirement, and might not b the same for all. Far too noisy and too many distractions. Plus couldn't really see another child like dd1 when we were looking round.
Jigsaw: more of a "proper" school in the way it is organised. plenty of outdoor space (and loads more on the doorstep!). less intimate and friendly though, more of the vibe of any old school (a plus poin for some, i'm sure, but it felt very impersonal to us)
classrooms still too busy for dd1 as she was then - too many people, too much going on for he to be distracted by. didn't like that things like SALT seemed to be given as small group activities only, no option for 1-to-1 (we may have got the wrong ipression here, but we did ask specifically if any individual work was done, and were told only taken out for small group work. we were asking more for general stuff, not SALT specific, but same answer. would not have worked for dd1 at all)
don't liek the style of ABA used. very data driven, and when we observed a LOT of time was taken by the tutors collecting this data - dd1 would have lost focus in an instant, switched off, and started misbehaving.
we also employed an ABA tutor who had previously worked at Jigsaw, and her views were less than complimentary.
having said all that, we had a really hard time choosing between the 2 (and of course dd1's current school) - al had pros and cons. I think ultimately we woudl have chosen Jigsaw if pushed, but that was probably due more to lifestyle factors sch as driving/where to live etc, plus the fact that Rainbow were really crowded out which would have driven dd1 mad.