Their customer service stinks, and their upgrade pricing also stinks. However, Data Rescue 5 was the ONLY software I tried (and I tried many, both for Windows and macOS) that would recover the files on my drive. I knew the data was there, that it was intact, and there were no hardware issues, but other software couldn't do a thing for me. Zero, zip, nada!
Data Rescue 5 took many, many hours to scan my 4TB drive thoroughly (So many hours I lost count. Maybe around 24 hours, give or take.) But in the end, it found all my missing video files. And totally intact, too. Playable as is. I did have to rename them myself, but that wasn't a big deal.
My case was pretty unique. My drive had been part of a home-made DVR I disassembled. My old DVR software was out of date and no longer supported, so I finally just gave up. But I did want those video files I'd spent over a year recording. The whole last year of David Letterman and CSI and a bit more. But however I had my drives configured with Windows, once I tried to read my main drive by itself, it just wouldn't work.
Data Rescue came through for me, but I still think their support and pricing sucks. In my case, I happened upon a Black-Friday sale after Thanksgiving, ($35 from MacSales.com) so it wasn't nearly so expensive as it usually is.
Considering their lousy support and usually very high price, three and a half stars was the best I could rate it.