I've tested 1.40 version of this program by dumping two discs:
1. After Hours Athletes BCES-01335 (perfect condition, dumps fine via multiMAN and matches existing redump entry);
2. LittleBigPlanet 3 BCES-01663/RSC (data side is heavily scratched, cannot be dumped via multiMAN due to read errors).
1. Dumping.
ManaGunZ 1.40 dumped After Hours Athletes game correctly. The hashes match redump entry.
Dumping LittleBigPlanet raised some questions. When multiMAN dumps a disc with read errors it does 30 retries on each error. If data cannot be read in 30 retries, then dumping process is terminated. This happens with my damaged LittleBigPlanet disc too. ManaGunZ on the other hand, continues to dump the disc without terminating dumping process. The read rate dips to 0 MiB/s in problematic areas as expected but dumping is not terminated. I transferred the output dump to my PC, calculated the hashes and they didn't match the redump entry. Now I'm not sure what ManaGunZ does exactly (forcefully fills error segments with zeros or something else) but it clearly is an issue when it comes to accurate dumping. I've had multiple PS3 discs which visually had perfect data surface but rendered read errors upon trying to dump them via multiMAN. With ManaGunZ there is simply no way to tell if such discs were dumped correctly. Moreover, as an additional indicator of dumping process status multiMAN features an active log which shows errors and retry attempts; ManaGunZ has no log and therefore no way to see if any errors were ever encountered during dumping.
Another thing I've noticed is that when multiMAN encounters read errors, discs would slow down and speed up again. In other words, one can hear how optical drive does something with the discs. In ManaGunZ nothing like this happens, just a steady humming of a dumping process despite the errors.
Dumping process of damaged LBP disc via ManaGunZ 1.40:
https://www.youtube.com/watch?v=E2Qr5mHiBwo
Dumping process of damaged LBP disc via multiMAN 04.85.01:
https://www.youtube.com/watch?v=Df6uDcv8uqk
2. Transferring the dumps.
My Slim PS3 has only two USB ports. One is occupied with the controller since its battery is dead. Dumping keys via GetKey requires FAT32 formatted storage. Dumping discs via ManaGunZ requires NTSC formatted storage (as a proposed method in the guide posted above). You can see how this becomes an absolute circus of constantly inserting/removing devices to keep the dumping process going.
ManaGunZ can dump discs to internal HDD just like multiMAN does but at the same time there is no FTP connection support. Therefore even if I dump a disc to internal HDD via ManaGunZ, I would still need to use multiMAN to transfer the dump to my PC since I use cable connection which is the fastest method.
3. Images' filenames.
One interesting detail of ManaGunZ is how it forces its own filename format on the dumps.
For example, multiMAN would name the above-mentioned After Hours Athletes like this:
After Hours Athletes.ISO
While ManaGunZ would render this filename:
BCES01335_20210710_063641.iso
This could actually be a solution for those users who encounter an outright termination of dumping process in multiMAN when certain Japanese discs are attempted to be dumped. They have either Japanese characters or nothing at all in their file/volume names and that, I guess, confuses multiMAN. ManaGunZ might be able to bypass this.
My resume would be that using ManaGunZ for dumping in its current state is not warranted. The way it handles read errors alone is reason enough. At the same time it might help dumpers who have issues with Japanese discs but imagine that those Japanese discs would have read errors as well, then it's a guessing game of was such disc dumped correctly or not all over again.