I bought a TD146 around 1983/84. Six months later, I heard a Linn LP12, which got so much more information off the record that I simply had to have it.
Well, I'd hope that was the case. I'm pretty sure that the TD146 and the LP-12 were never intended to be in the same league.
Thorens tables can be finicky beasts, though. You've got to be sure that you've got all the set up parameters accounted for: the table is level, the suspension is properly adjusted, the belt is new or in good condition, the platform that the table is sitting on has to be free of room vibrations, foot falls, etc., the cartridge is aligned and VTA adjusted, etc., etc. Once all those parameters are accounted for, then you can start tweaking.
The Thorens will likely be competitive with the 704, and may actually outperform it in the rumble department. The Thorens also may have the better tonearm of the two. In terms of absolute ability to be faithful to the recorded signal, a properly set up Thorens may be the winner between the two tables.
The 704 will have accurate rotation speed, and likely be a lot less finicky about set up. It has a decent tonearm, and is a bit less susceptible to vibrations (though it will still skip with a decent foot fall, unless mounted on a shelf or in a room with a concrete floor).
So, some of this is base on your preferences as to which table meets your needs. I'd likely opt for the Thorens, with the understanding that it might need some tweaks to get the most out of it.