Although the x3 is not exactly super high precise machine it seems well designed. If I am looking at the pictures correctly it has a little over 8" on the table for ways which is more then half of the table contacting at once. If you through up a 600 piece of iron on the table on a regular basis I think you may have issues. Its been my exeperice that over zealous operators over tighten the gibs and cause more damage then anything else. As was the case on a friend of mines atlas mill.
One of the beauties of iron is that you can scrap it back(or grind if desired) should it wear more then desired, you could I suppose use Moglice and build it back up should it hollow also. These machines have been around for awhile now and I am sure there is someone who has worn theirs out but I have not heard about it on any regular basis. Machines like this design were used for years on 3 shift operations before they needed to be scraped, granted that was US iron, and in alot cases alot bigger but the formula is still pretty much the same. If you keep it lubricated, level, and un abused it should more then likely out last you. I have not seen nor heard of the any mods to the table to increase rigidity or tolerance other then the typical cnc mods.
I would be more worried about the spindle or motor long before the bed. My thoughts at least, I am awaiting a break in the snow to get my x3 ordered so I can get it home. If I have to wait much longer I might as well order the Sx3.