When the used market price dropped to under $1000 usd for the 1D3, I jumped. I'm glad I finally got a 1D3, and it does everything I need it to do, but the technology is dated.
Still, it's a workhorse with fast and accurate AF. IQ is great from the APS-H 10mp sensor, and as long as you compose correctly, iso 3200 is usable. However, if I need higher iso performance, the 1D3 will sit in the bag with my 6D getting the call.
The 1D3 menu system, along with dedicated function buttons and a SET button, are welcome upgrades from the 1D2. The 3 is also lighter than it's predecessors, but it still is a hand-full.
The 1D3 is a good tool when one needs a fast operating, fast AFing and robust body, at a now reasonable admission price.