Review: Samsung A900

... The 90 day limit is in effect for users of new handsets (so they are not able to just re-download all of their previously purchased content).

Well, then it sounds to me like the review is pretty much correct. If you spend money to "buy" a ringtone from Sprint, you should own it.

They have the ability to offer it to you with no time limit at no extra cost or difficulty for them (trust me). The fact that they don't let you do that - and in fact go to extra effort to impose a time limit - means to me that they're not selling you the ringtone to own.

You just said they want to sell you the same ringtone again if you get a new phone. That's not "owning" it. That's renting.