Well personally I have Digitranslator (even a spare license I think).
And IMO you do lose quite a lot of functionality by using PT5 format sessions, especially if you started off in Pro Tools 7.3 or higher!
Because of the encryption methods mentioned earlier PT5 is the only option.
Even Digitranslator (and ProConvert) has limitations. The thing to realise with any daw convertor or translator is that no matter what there is a loss of some sort. This loss can be significant or trivial depending upon the source and destination.
The AES31 specification for transferring between daws was an attempt to bring some form of standardisation to this process (BTW PT disregards this standard completely) and even that has limitations.
Moving between daws is not a trivial matter and I certainly don't recommend it but if it must be done then it should be done in the early stages of the project.
Eg Band tracks in a PT studio but wants to mix their own stuff on (insert other daw name here). Or they may want to record their own guitar tracks and then bring the lot back to the studio for mixing.
We had one the other day where they wanted to take their tracks/clips etc away from my studio (recorded in Audition) to mix themselves in Vegas.
Thats when translator software is most useful.
It is not recommended to be moving between daws once you have applied fx, plugins etc.
Either way each daw producer should give you a relatively easy & inexpensive way of getting your tracks in AND out. IMO this should be a trivial exercise for the makers of Digitranslator and in no way justifys its price.