Never tried the spinosad yet.
I battled thrips for a long time and this is how I killed them:
Pyrethrin based bug bombs, set off at 4-5 day intervals, 2 or 3 times. Even Raid makes one. It's in a blue and yellow box. DON'T USE IT PAST WEEK 3 OF FLOWER!!!! This allows you to kill larvae that are only just emerging from the protection of the plant's meristem, and adults that are just coming out of the soil instar.
Mist lightly with neem every week to help prevent reinfestation.
Alternate with a pyrethrin based spray.

I am hearing excellent things about spinosad btw.