Zenith made four solid-state Trans-oceanics (not counting minor variations within each): the Royal 1000, Royal 3000, Royal 7000, and the R-7000. As a very basic comparison: the 1000 was the base model; the 3000 added FM broadcast reception, the 7000 added weather and aircraft "bands." The R-7000 covered all of HF, not just world-band segments. There was also a Royal 2000, but it only picked up commercial broadcast AM and FM, and isn't truly a Trans-Oceanic. I don't know why there was no 4000, 5000 or 6000 models. If I ever meet someone from Zenith's marketing department, I'll ask.
There were a lot of differences which are described in detail and better than I would do, on other websites. A Google search should pull up several on the first page of results.
This one is mine, acquired for a price I was willing to pay. I always thought it would be nice to have one but usually they're too expensive. (The killer is the R-7000, which is at least a couple hundred dollars even in mediocre shape. I'll discuss that one if I ever find one I think is affordable.)
The 1000 and 3000 are largely the same machine except that the 3000 includes FM broadcast. The 7000, on the other hand, was a redesign inside and out. One of the neat things is the new cabinet. The front panel still drops down, but unlike the earlier models, it pushes in underneath, so if have this on the edge of a table or desk, the front panel doesn't stick out, or flop down and toss the log book onto the floor.
Current status: purchased: in-transit.