I've had it done. I'll try to describe my experience without getting too wordy.
Our garage had some drainage issues which cause the floor to drop. At some point the previous owner had it mud jacked which must have helped temporarily but they didn't solve the water issue. I fixed the drainage issue then worked on the floor using the poly foam injection.
One thing I noticed was although the holes are smaller, there are more of them. Watching the process it seems like the foam lifts are more pinpoint and the foam doesn't flow like mud jacking seems to. As a result we ended up with a few more cracks in the slab. Not a big deal appearance wise given where we started. My observations are purely an uneducated opinion based on what I was watching.
I also had a portion of the front porch done with no ill effects so I suspect the large slab of a garage floor is just more fragile given the large flat area vs a compact porch.
I'd do it again if I was in the need. I've since sold the house so I can't speak to long term results but I suspect since I fixed the water into the garage the problem was solved.