Although it is advertised as "automotive" oil, it is recommended by Piaggio for the Medley 125 and 150. I am surprised that it is not widely available in the market. It seems that either authorized workshops monopolize it, or users have overlooked it, using some other oil with similar specifications (which one, I wonder?) or maybe even some "scooter" oil like Castrol Power 1. The latter case, of course, seems prohibitive. Now, regarding the Eni lubricant, I have to say that I have not tried any other on my own Medley in order to make a comparison, nor did I have any previous experience with scooters in general. However, the engine seems to work smoothly, relatively quietly, and satisfactorily for a 125cc. It might consume around 30-40 ml per 1000 km, I'm not sure, I will make repeated measurements. But even if that's the case, it is considered normal for such a thin oil. The price I found it for was 13 euros.
Update 16/4/2019. A few days ago, the mechanic changed the oil and filter, using the aforementioned lubricant on the scooter, but he also told me that Piaggio now recommends a corresponding Castrol lubricant. I'm not sure which oil it is, and even the mechanic doesn't know yet. It is likely to be one from the Castrol Edge FST series. However, be careful because there are at least two with 0W30, and logically only one is suitable. If someone finds out, please inform the public.
Update 2/6/2021. (Comparison between Eni and Castrol) It's been a week since I put the Eni oil back. I had also used the same oil in December after using the Castrol Edge Professional FST 0W-30 two or three times. Both lubricants have shown excellent care for the Medley's engine, but surprisingly, even though I'm a fan of Castrol, I conclude that with Eni i-Sint Tech 0W-30, the engine runs slightly quieter and fuel consumption is 2% lower. Oil consumption is almost negligible with both lubricants.
Update 5/10/2023. The verdict: Five and a half years, 45,000 kilometers, and there is no chance I will use a different oil in my Medley. Now I change it every 7,500 kilometers without worry. Negligible oil consumption and a happy engine.
Tip: Change your oil at least once a year (depending on mileage) and ideally in June.