The real use of regen programs like Spinrite and HDD Regen? None at all I guess. You shouldn't use them on any failing drive, and there is no reason to run them on a healthy ones. I picked up a license for Spinrite some 10-15 years ago. Did successfully use it to recover data from 5,25 and 3,5 inch diskettes. Never used it on a HDD though. The main problems of the "regen" approach are stressing the failing HDD, and writing recovered data back to the same disk. Maybe this did work back in the era of very low density HDDs. Today it is not a valid approach for recovering data.
MHDD has indeed got a scan and repair function which not should be used indiscriminately. But MHDD has also got other tools which can be quite useful.
When it comes to software programs for cloning, Media Tools Pro is doing a decent job. Other software tools to look into are HD Dupl/Copyr and ddrescue. Please note that cloning programs based on only software are limited in how they handle HDD errors. Cloning a disk with lots of media errors can take considerable amounts of time, if possible at all.
An important principle for both hardware and software based cloning solutions is to only attempt repeatedly reading difficult sectors after all easily readable data has already been saved. In other words the cloning program need to address the HDD in different phases, using a log file to keep records of what's done. Increasing sector read retries for each phase.
If you browse around these forums you will find lots of information on cloning. E.g these links:
Procedures for cloning Sata and Pata hard drivesThe Best Disk Cloning Hareware/Software