Here are some tips to help you evaluate speakers.

Make side-by-side comparisons.

Our acoustic memory is short. It’s hard to remember Speaker "A" if you have to go to a
different room to compare it to Speaker "B".

Listen to speakers at equal volume.

Even small variations in loudness can easily be mistaken for differences in sound quality.

Turn the video off.

Eliminating visual distraction will help you focus on the sound, even in a home-theater demonstration.

Listen for clarity.

Are the speakers clear, natural-sounding and intelligible with instruments and voice?

Listen for a "seamless" soundstage.

The speakers should present a broad, cohesive image of the original sound.

Listen to the bass.

Is it deep, tight and well-defined?

Sit up straight, then slouch.

If you hear distinct changes in sound quality, the speakers may have a deficiency in their vertical dispersion.

Move around.

Good speakers disperse sound over a wide listening area. Move around to find out what others in different listening positions will hear.

Following these tips will help you control the variables and compare "apples to apples". Take your time and trust your ears.