Nothing has changed in this matter.
Whether you should do it or not, well that depends. By default ntext is
always stored out-of-row, whereas the MAX types are stored in-rowm when
they are below 8000 bytes in size and fits on the page.
If your data is typically always over 8K in size, it does not matter. But
if most rows have data in the 1K range, you reduce the amount of LOB pages
you need. Then again, if this means that many of the other columns spread
out over a lot more pages, so scans that does not require the MAX column
will be slower.
So there is on straight answer to this one. But altering the column to be
MAX is always a good thing, since there are so many restrictions with the
old types.