Years ago, I used the Paint Shop Pro 1-step fix option, which worked great but took some time on each photo as it ran multiple passes of improvements. It became cumbersome despite having a batch option and I don't even remember when I stopped using it.
Now, I see "auto" fixes in Google Photos and the Windows 10 photos app. They both seem to do a pretty good job. They still take some clicking around, though. What's your favorite among these tools for the lazy? Are there any that apply as a filter automatically as you view the photos? They are pretty much instant so they might as well allow a toggle to apply automatically without overwriting the originals.
The "One Step Photo Fix" option in PSPX8 Ultimate uses, I believe (don't have that box near me at the moment) the "Perfectly Clear 2 SE" version Of Athentech's extremely efficient corrections algorithms, and running it in batch is a piece of cake.
A couple years ago I spent quite a bit of time comparing the couple seconds PC2 takes for corrections (via standard option above, but you can actually fine tune this by opening the plugin for individual pics) with the huge amounts of time and pain spent in PS6 on each pic and I realized how unbelievably good Perfectly Clear is - it works amazingly well on JPEGs but I also ran it at default setting on hundreds of ancient family slides and negs which I had scanned as high-res TIFF files. I could not believe the amount of improvement, with some pics going from from a muddly mess to enough sharpness and resolution that I was actually able to print them - some brought tears to the eyes of my elders, and for that alone I will be eternally grateful to the folks who spent time producing this software.
This being said, Athentech has since rewritten everything from the ground up in V3. I actually considered buying it but there are a few things on their site that do not inspire a whole lot of confidence (no email list signup option on main site (WTH?), no clear table explaining the differences, if any, with their Lucid software, no standalone version that I could find, no downloads section with list/dates of bug fixes and improvements, fairly high price, plus they apparently do not know that we are in the year 2017...)
Anyhow, I would love to see comparisons with comparable tools from other software companies (does ACDSee have such a tool and how does it compare for example?) If you have actually have experience with this yourself, or know sites who have done it, please chime in!
Hope this helps.