For bug-out I might prefer one of the plastic models. The are much less sensitive to moisture, usually cheap and probably good enough for most of us.
For use in non-emergency scenarios I got a Hohner Marine Band. It makes a difference.

+1 on the Hohner Marine Band harmonica. The Marine Band 1896 is a classic and the price is not out of reach to even a beginner. No affiliation, I'm a beginner and I'm not even big on blues.

I sometimes bring an Irish Whistle. I don't know how to play it but I enjoy playing with it.

I'm partial to the Lee Oskar diatonic. They're a bit cheaper then the Hohner's, completely synthetic (stainless, brass, and plastic) and have a bright sound that projects a good distance.

Is that brighter sound true across all 13(?) keys? If it is that would be a good signaling tool in a survival situation. Maybe not as good as some of the louder whistles, but dual purpose is often a compromise.

You're not going to match a whistle with a harmonica. If I had to guess, I'd put the max volume in the mid 80's Db.

The bottom range (below middle C) can be a little muzzy unless you have a good air column. Keep in mind that there is no such think as a "melodic" harmonica. They all sound like jazz saxophones. The L/O just tend to be brighter than most.

EDIT: Depending on how bad you are, it just might work for critter protection. A bad harpist sounds like a goose in the washing marching.

Around here the Hohners and the Lee Oskar are about in the same price range. I prefer the Hohner because I like the touch and feel better and I like their sound.
I have a Hohner Echo for 40 years now and it still plays fine. That kind of makes a small price difference less relevant anyway.

I got some good advice for buying instruments from a music teacher. He advocated buying a decent instrument especially for beginners.
A "beginner level" one is harder to play nicely and frequently destroys interest. A decent one keeps a higher resale value. Once you reached advanced level (and sometimes beyond)you got a decent instrument you are used to.
The only reason I have a Hohner Happy Color harp is because it came in a set with book and DVD. The instructor on the DVD plays a decent blues harp. Good luck trying to match the "it should sound like this".

After reading this thread, I went and checked out some harmonicas on Amazon. And went to Youtube to hear a few played (by people who know how to play well!)

I have to say,the harmonica is just not for me. Everyone has personal preferences, but I just don't care for the way they sound.

Mark_R mentioned an ocarina. Those sound much more pleasing to my ear (not the high pitched ones, I think "tenor" or lower sounds better).

Now I think I may have to go investigate buying an ocarina. I was thinking of learning the pan flute a while back, but an ocarina would be much smaller and easier to carry around.

Learning the harmonica will be a journey and it may be interesting. From what I heard on youtube there are different techniques and sounds, but it may result in my gifting it to someone who can appreciate those tonals.

OTOH, I like the sound of the alto recorder I recently purchased, the problem is while it is supposedly sized for adult hands, maybe there's a fingering technique I'm missing because it does not fit my hands (and I don't have small hands). I'm going to try a soprano recorder and see how the higher tones sound compared to the alto. An alto recorder typically covers 349-2093 Hz and the soprano covers 523-3136 Hz; that's a significant shift. There's a chart at Recorder Frequency Ranges that may be useful. Per that chart, age related hearing loss starts around 2000 Hz. As I recall my hearing starts to significantly fail around 4000 Hz, so we'll see where this all ends.