In the modern sense of the word cult and the particulars of the behaviors we associate with cults, I would say the modern LDS is perhaps 'cult-lite'. They have a number of habits that are typical of cults, but they aren't nearly as oppressive to their members as groups like Scientology are, and you probably wouldn't be too hard pressed to find some Christian churches that have a similar level of cult behavior.
Now on the other hand, the fundamentalist Mormon groups that still practice polygamy, force male children onto the street to do so, and stay very isolated are most definitely full blown cults.
I believe the mainstream LDS church has nothing to do with the fundamentalist LDS like we saw in West Texas and polygamist leader Warren Jeffs. I'm sure even Joseph Smith would be turning over in his grave knowing what Warren Jeffs has done with the church he founded.