Our experience may be unusual but we got the school testing first. DH and I believed DD was likely dyslexic and I knew she had fine motor/ hand eye coordination issues for years before we could convince the pediatrician to have her evaluated. The extent of her issues absolutely blew away the school psych doing the testing. The benefit was that it was done quickly and we were able to get services up and running immediately. When she started to experience severe headaches we ran her school results by Paul Beljan via a telephone consultation and he told us the get her to a neuropsych eval PDQ. Unfortunately we had a bad experience and paid $3k out of pocket for a set if results deemed to be "invalid." Our consultant got the district to pay for a new neuropsych eval but we then had to wait for an opening.
So... I guess the bottom line is that the neuropsych testing (done well) is the best route. It can be expensive, though, and can take a long time to get in to one, especially a good one. You will get more detailed results and (hopefully) recommendations from a neuropsych eval but there is no guarantee your district will accept the results. A school evaluation may be a good way to start if you have specific areas of concern and you want to get services up and running quickly.
I guess knowing what I know now I would have gone ahead with the school testing (it turns out that everyone agrees the school psych did a surprisingly good job) but scheduled with the neuropsych at the same time. It can take up to a year to get in to see a good one. Just make sure when scheduling that (s)he knows what tests were previously done so your appointment is scheduled in a way to avoid "retest artifact".
Also I would not wait to do vision testing. I say move forward on all the fronts you can.
Good luck!
