rowtc2 - 11:07 am on Mar 11, 2013 (gmt 0)
I have put some pages with 410 status code and some pages with 404 status code.
Pages were removed from SERPS in ~3 months, i do not think Google makes a difference about how treat them.
Also, i think is important to not have internal links pointing to 404 pages. Even you do not have internal links pointing to 404 pages, Google still see 404 pages from indexed/cached URLs from a date when that page(s) have a link to actual 404 page.
These days, because they make often algo updates, is hard to say if 404 casue a drop in ranking, but my feeling is if you do not link internally those 404 pages, should not hurt (otherwise a competitor could put thousands of links to your site, to different 404 pages, and hurt your rankings).