Some reading material, and it is probably true.
Replacement Tool Batteries: Third Party Savings |PTR
One question you might ask yourself, does the generic battery have the electronics to protect the battery and tool, and are they using some of the best cell manufacturers.
I don't know about the generic batteries, but I trust Milwaukee to be true and honest with their products.
Another question, can battery re-builders, rebuild a battery as good as the original or better.
Here is my question to a Ebay seller for the M12 2440 battery.
I asked, can you certify that your 4.0 amp battery can operate for 4 hrs with a 1 amp discharge rate.
His answer.
1A would discharge about 3.5 Hour
Because the Milwaukee original charger will not fully charge the battery in order to extend battery life. The milwaukee charger will charge to 4.1V then stop, so battery will not fully discharge for 4 hours.
Some answer. Any one understand what he said.
One of the re-builders posted this.
The 2440 are rebuilt at 4.0 Ah and the 2402 at 3.0 Ah.
Thanks,