Anyone know anything about stereo ohms, etc.?

I just got a very nice stereo receiver. If I'm understanding this correctly, it has the ability to put out at 4 ohms if need be. The manufacturer reads a certain number of watts at 4 ohms, or more watts at 8 ohms. I'm assuming that means that the receiver can drive either 4 ohm or 8 ohm speakers, is that correct?

I'm also under the impression that 4 ohm speakers are better than 8 ohm speakers. If so, why? I'm guessing 4 ohm can deliver a much more pure sound. Next, will 4 ohm speakers hurt an amp that is NOT 4 ohm capable, or will the amp hurt the speakers? From what little I could gather on this from the tons of opinions on the internet, is that if you have 4 ohm speakers, it will ultimately toast your receiver.

The stereo output is actually limited to the amount of CURRENT it can safely put out. Knowing ohms law, the mfg takes the known applied voltage and maximum current and converts this to the RESISTANCE of the speakers one should hook up. R=V/i. But let us think CURRENT in terms of i=V/R. If R is too low (voltage is fixed) then I (amps) will go too high and either open the power supply fuses or let smoke out of the wires (burn up some components)

1. I'm assuming that means that the receiver can drive either 4 ohm or 8 ohm speakers, is that correct? All things being equal, 4Ω will handle 2X as much current as 8Ω speakers.
2. I'm also under the impression that 4 ohm speakers are better than 8 ohm speakers. If so, why? Sounds better depends on other characteristics but LOUDER is BETTER (generally).
3. Next, will 4 ohm speakers hurt an amp that is NOT 4 ohm capable, or will the amp hurt the speakers?

The speakers will attempt to draw MORE current than the amp is safely capable of handling. When in doubt - follow the mfg recommended instructions. If there is a help section on the mfg website - give them a call when they are on available hours.