Integrated used as Preamp?

Can anyone comment on using an integrated amp solely for its preamp as opposed to buying a pure preamp? Reason I ask is because I have been eyeing a few Musical Fidelity preamps (such as the A3cr and A3.2) for a while but the integrated versions go for cheaper than the pure preamps. Why spend $150 more to NOT get the amp inside? I don't need the amp but why spend the extra money? Is there anything APPRECIABLE one should expect to lose from using the integrated instead of a pure preamp?