In theory you shouldn't hear anything different. A speaker's job is to reproduce the input signal that's fed to it.I've actually never owned Home Theater speakers before. Only Hi-fi speakers. What will I hear that's different compared to the hi-fi speaker's?
In practice, most hi-fi speakers are voiced to be smooth sounding so as not to be fatiguing to listen to. Most home theater speakers are designed to be very dynamic, such that short duration loud events (think gunshots in movies) are reproduced well. Many times this leads to home theater speakers sounding harsh, though I've not noticed that with any of the diysoundgroup offerings.