@acuriousman

By idea, one that sound like you are in "soundproof studio " is better if you have serious projects. As adding reverberation and additional life sounds is easy, and removing it all is almost impossible.

Haavard's got one part of the equation already but here's a slight expansion.

When dealing with microphone sound, here are some of the biggest variables.

Diaphragm size: One of those microphones is a large capsule condenser (also called a large diaphragm condenser), the other is a small capsule condenser (also called a small diaphragm condenser). Large capsules can more easily be designed to maintain a low self-noise floor than small ones but they also are more difficult to design for an even frequency response in the higher frequencies. Typically, if you look at the frequency graphs for large condenser microphones, you will see peak and variations in the higher frequencies that are different from the response below that point. In some microphones this is intentionally emphasized or exaggerated which is sometimes the case when someone talks about how a microphone makes their voice "cut" through a mix. By contrast, small diaphragm microphone will tend to be difficult to design with low self-noise but will often have flatter high frequency rendering by comparison.

Microphone type: Generally, people will most often talk about condenser (one of the most common lowest noise modern types), dynamic (very common in rougher vocal situations, especially ones where you don't need the extra sensitivity of a condenser) and ribbon (a variant of dynamic microphones and pretty much the only game in town in a lot of old vintage recordings, among other things). Both of the microphones you listened to are condenser microphones, so the variable doesn't apply here but if you ever compare a condenser microphone to a ribbon microphone, you will notice a huge difference. Here's one quick way to listen to such comparisons. http://www.zenproaudio.com/clipalator.aspx

Pick-up Pattern: One microphone can have multiple switchable pick-up patterns and @haavard already gave a link to some explanation of it, but here's the cliff notes. The pick-up pattern determines what sounds around the microphone (by angle) get picked up or rejected. The pick-up pattern determines the extent to which a "proximity effect" (whereby the low frequencies are exaggerated as the source of a sound gets closer to the microphone) comes into play (with cardoid having a lot and omni having almost none). To an extent, the pick-up pattern also determines overall frequency response and the "directionality" of the sound. Directionality (in this context) being the extent to which a sound changes as the angle or position of the sound source is varied relative to the microphone (with hypercardoid being one of the most directional, cardoid being somewhat less so and omni being the least).

In addition to these factors it's worth considering other aspects such as whether a microphone is solid state or tube (not a differentiating factor in your case), the impedance (one of your microphones has 50 ohms vs 250 for the other) and a whole lot of other other factors that help to give a microphone it's "sound".

But the shortest answer is that variation in sound among different microphones is both desirable and well understood by most recording engineers for the purpose of being able to quickly able to pick the best microphone for a given task (or to get the most out of a microphone they have to use despite it not being ideal for a task) and that there are many variations in the sound of "similar" microphones from different manufacturers that go beyond most of the variables discussed here.

There are lots of great microphones and not all of them are expensive. If you end up wanting some extremely durable omni pattern mics at a low price, then these are some of the best I've heard my colleagues use (though I've yet to try one myself).

http://littleblondie.com/

If you want inexpensive ribbons, I'd look at some of the ones from Cascade microphones.

It's a huge can of worms (and I come at it from a recording studio background more so than a live sound one), but I hope that you're enjoying what you're finding so far.

Maybe same reason of human voice? There is no same voice among billions of people. Same meat, similar dna, but always different...

The material used to build, the way it is built... results in a timbre, stamp, colour, frank, tone... (in industry, same model = same sound, due to same construction, but different model = different sound)

http://en.wikipedia.org/wiki/Timbre

If you had two identical microphones and placed them one foot apart they would sound different. The design of the capsule and the materials of the capsule are important, but even the grille affects the sound.

@acuriousman the best advice I can offer is using any 2 same directional mics like 4047 you mention, when you need isolation use one of them, when you need real ambience cross the centers of mic's capsules in 90 degrees and use one for left channel, the other for right, no mix of them. Recording stereo like this is much better from almost any self omni cardioid mic.