As chitown said, all balls absorb oil and all have a limited lifespan. Some might give you 100 games, even with good maintenance, some might give you 500 games with modest maintenance. Ebonite and Ebonite-owned brands have a reputation for shorter lifespans than other companies' equipment, but people absolutely love the reactions while they last. There are a lot of posts about Ebonites and Hammers going kaput after 100 games or less, I don't see posts like that for some of the other companies.
It also depends on the particular coverstock used, it isn't simply "all Ebonites". People have thrown V2s with many, many hundreds of games and are perfectly happy with the ball reaction. But the new generation of oil-absorbing covers from Ebonite (Traxion on the NVs, GB on The Ones, Violent on various Hammers) seem to have a shorter lifespan than other covers.
SH