have tried a few of the other ones ,
but my thoughts are that Google has more voice info than any of the others and the $$$$$ to throw at it ,

But it is great that they let other use the Translate App (engine) to build better Apps which helps google ,

I would love a Tablet that would be OK Google , google translate and text to speech in all the main languages ,
And that you could download the language you need to use and be able to "talk" offline in some remote village.

This would really help open up the world

But right now I am happy with what I have learned here , as the last time I looked into this it was not very good ,

I am sure we will be amazed at what this tech will bring in the future