I like the 3rd and the 2nd one, because they are more clearer on the different screen aspect of the company and they looked most decent. I think that the first one is too simple, not really explaining the idea of the company (but it's in the name, so I don't think that it necessarily has to) and on the last one the symbol does't look that good, with the 3rd example at lest you done much better job. But I think over all they all are pretty good.