As for whether its any good or not, it depends on what you are trying to use it for. You definitely don't want to become dependent in it. The withdrawl is like a long drawn out panic attack. It is useful for getting into a social mood and preventing anxiety. A dose of phenibut is like a few beers, but it lasts a long time. It's also not as "messy" as being drunk. A large dose, however, can leave a person vomiting with the spins and bad muscle twitches (myoclonus) for a very long time.
I had one friend who was an alcoholic and despite having had a liver transplant, she started drinking again. I introduced her to phenibut and she said it kept her cravings for alcohol at bay. She did OK on for awhile. Similar to how methadone can be used to treat opioid addictions, phenibut can be taken once a day to substitute for alcohol. It is not by any means a "safe alternative." In contrast to alcohol, it is not taxing on the liver but may be taxing on the kidneys (staying hydrated may lessen the load.) It could also be used as a sleep aid although it takes up to 4 hours for effects to manifest.
As for comparison to benzos, phenibut may have similar uses but the effects are closer to alcohol. I would not call it "tamer" than a benzo, but it's not as likely to cause blackouts and reckless behavior. It can potentiate other GABAergics, but may provide unpredictable results and can be a recipe for an overdose. Underestimating the addictiveness and just plain over doing it has caused people problems. On the flip side, some people can use it in a responsible manner as a medicine. Though for daily use it is a poor choice because tolerance develops rapidly leading to higher doses and addiction.