Choosing a translation system

[Warren Block]

PO/gettext tools appear to be the default choice for translating open
source project documentation.

There are some disadvantages to it.  Two that have been mentioned to me
recently are:

   Different translators can translate the same string into different end
   results.  (A list of standard terms could help with this.)

   Strings are shown alone, without context.  The meaning of a string
   shown with surrounding text can be much easier to understand.  (A
   sufficiently advanced translation editor might be able to show
   context--are there any?)

What other types of translation systems are available?