allofmp3.com has come under a lot of scrutiny in the past, and so far has escaped prosecution because of a loophole in the Russia legal system...there's a technicality in the way the laws are worded since they haven't been updated as technology has progressed. Thus, it is technically legal in Russia for the time being.
In other countries, it's up for debate. In the United States copyright law there is an exception that pertains to importing single copies of music from other countries for personal use, and there is a similar clause in Canadian law. However, those laws have not been updated along with technology either (the wording refers to a physical copy, not digital), so depending on the interpretation you may or may not be committing a crime. In addition, other laws may be read in a fashion that they contradict this.
So far the RIAA, MPAA, and others have not targeted allofmp3.com or any of its users, but now that the major P2P services are being forced to shut down it's just a matter of time before they turn their attention to such websites.
It's comparable to using Napster (which is now legit) before the crackdown on piracy:
* Was it wrong? Yes.
* Was it piracy? Yes.
* Was it legal? By a technicality.
* What happened? The laws were clarified and strengthened.
* Were previous downloaders prosecuted? No.
* Are current downloaders prosecuted? Sure are, by the thousands.
Thus, the decision to use them, and feed the pirates, is up to you, but I'd stay away, following my morals, ethics, and principles instead of exploiting a loophole for my own personal gain on the dime of others.
John