I notice you are in a fairly distant land. From my experience buying used, you are probably better off buying new if you need to have it shipped to you.
I bought used both an ATL-1 and an ATL-1000 and both arrived damaged. They were not shipped in their original boxes, so UPS refused to honor a damage claim. In the case of the ATL-1000, the shipper was a big UPS shipper and insisted the claim got paid.
On another note, older processors like the ATL-1 can need some work on the computer head, such as replace an on board battery in order for programs to be remembered.
For the ATL-1000, the E6 and C41 processes are preset, so you cannot fine tune the time like you can with the ATL-1500. If you are just doing roll film, the ATL-1000 or ATL-1500 are the best processors because they are more automated. Will all of the automatic processors, you need a tempered water supply, but with the ATL-1000, ATL-1500, you can just load the film, fill up the chemical bottles and walk away. When the chemicals come up to temperature, the process will start. On the other processors, you need to measure the chemical temperatures and then start the process when they are up to temperature.
Robert