differences between x != 0 and not(x = 0)

Hi all..

I always forgot this thing.

If I want to test that all nodes has value different from 0, I have to
use x!=0 or not(x=0) ?

For example,

<row>
  <x>0</x>
</row>
<row>
  <x>4</x>
</row>
<row>
  <x>0</x>
</row>

The test for the above example should return TRUE.

<row>
  <x>0</x>
</row>
<row>
  <x>0</x>
</row>
<row>
  <x>0</x>
</row>

The test for the above example should return FALSE.

Thanks
Jaime