Hi Diana

I went through this same discussion with a client of mine. Only the other way round - ie should he go to local domains rather than the .com that he has. I did a lot of research and came up with the conclusion that local domains are great IF you have lots of local resource to support the site - for local content, local links, etc. If the resource is there then the main benefit is that people in each country often favour visiting sites with a country domain.

Otherwise, If the resource is not there then you are better off with a .com domain where the focus can go towards building overall authority for just 1 site rather than many - as you say, it helps with the link juice. Languages can be placed in subfolders (/de/ etc) and that way Google will know to return the correct version in the country Google version.

Hope that helps - good luck