In case people missed it, after an embarrassing false start, pdf copies of the records are online again at: https://civilrecords.irishgenealogy.ie/churchrecords/civil-search.jsp
Deaths & Marriages during the 20th century revolutionary period may be of particular interest to some forum members.
Births: From 1864-1915, you can see the full details for births registered in all of Ireland. The cut-off date is 100+ years ago on a rolling basis (so next year 1916 births will appear, etc).
Marriages: From 1882-1940, as above but 32 counties to 1922 (-ish), ROI only afterwards. Date must be 75+ years ago.
Deaths: From 1891-1965. As for Marriages above, but date cut-off is 50+ years ago.
(Images of marriage and death records before 1881 & 1893 are planned for release online in the future).
These are all free and downloadable.
I've found a few records not online despite being available in the GRO research office. But that would be unlucky in most cases.
Spelling variations (more like errors) I have found a bit of an issue, but not a very major problem if you get creative with search terms.
So luck & good hunting!