aakk9999 - 8:11 pm on Aug 29, 2013 (gmt 0)
From all the research I've done and past experiences I know that it is important to set up the 301 redirects on a page-to-page basis such that sub-folders and deep content pages are redirected to corresponding sub-folders and deep content pages on the new domain.
Your research is correct - the best is to do redirects on the page-to-page basis exactly as you have described.
The danger of having a number of URLs redirecting to the same page is that Google may be treating them as "Soft 404 errors" instead of treating them as a redirects. Here is one recent thread where this particular issue was discussed: [webmasterworld.com...]
I've never done it on a directory level and haven't read much out there on that topic so I was hoping someone here could help.
I am not sure what do you mean when you say "on a directory level". If you are referring to URLs ending with / (which are by definition "directories"), they normally display the content of the default index page (e.g. index.html or index.php etc. depending on your server setup) even though the default index page is not seen as a part of URL (this is the best practice).
In this case you should be redirecting directory URL to another directory URL.
If you haven't meant this, then could you explain better what do you mean by "directory to directory" redirect.
Soft 404 signal bad technical quality of the site to Google. If Google treats these redirects as Soft 404, I am not really sure what effect this has on link juice, but (speculating) it could mean that is not passed on. Definetely not worth a risk.