No question with TestDisk as an excellent open source/free recovery option.
It was the only thing I found (freeware or pay) that relatively easily restored a couple of NTFS logical partitions--and all data--after they were destroyed by an older version (8.0) of Diskeeper's "boot optimization" defragging. The last time I used Diskeeper or recommended it. I continue to use and recommend TestDisk. The author of TestDisk was also responsive to emails when I encountered a unique issue with the drives I ended up needing help with.
Note that TestDisk is only for recovering lost partitions and making non-bootable partitions bootable again. For those functions, there is no better program out there.
Its sister program included in its download--PhotoRec--can do file recovery. Its designed mainly for recovery of photos off all media, but it supports many different file formats. So the TestDisk/PhotoRec package may be all you need.
Other freeware/non-open source file recovery alternatives that are reliable and work well:
--PC INSPECTOR File Recovery. 100% free & full featured, many options. Been using it for years.
--Recuva. 100% free, by Piriform, the maker of the very popular CCleaner/Crap Cleaner system cleaner.
Somewhat less elegant than the above one. But the only freeware option I've studied that can do a "deep scan" of your drives for lost files. Which can take hours, but may turn up more missing data than the other non-PhotoRec options here.
--EASEUS Deleted File Recovery. A more limited version of their $70 "EASEUS Data Recovery Wizard", but very well designed for basic file recovery.
There are other freeware file recovery options I've studied, but they are all more limited than the above. Would recommend TestDisk (for partitions) and PhotoRec (for files) first, then the other three (for files) in the order given.
In all honesty, shelling out for a payware solution is very unlikely to "find" more deleted files on a NTFS partition than the above freeware solutions, unless you have special needs they don't cover. Which is rare. And again, there is nothing better than TestDisk--free or payware--for recovering partitions.