Re: Tell me about the Fender Mustang...?
...If you want the security of a Poplar rather than Basswood body (which IMO is pure superstition), then only a newer 65 Reissue has that (one of the ones with no contours). But IMO, the earlier 69 reissue, as you have the downpayment on, is a **** fine axe

And you got it in one of the best color schemes
The switching system, however, is NOT the same as a Jaguar's (and a Jazzmaster has a completely different system anyway). UNLESS you accidentally bought a Cyclone II and not a Mustang (which is still not quite a Jag's switching...)
Because CIJ Mustangs with the racing stripe are fairly scarce, I slightly suspect you may have bought a Cyclone. The easiest way to tell is that if your guitar has a Strat bridge, it's a Cyclone. Which is ok, but you wanted a Mustang

Please post a pic so we can be sure. Also, if you have 3 pickups, it's a cyclone.
ANYWAY. On to Mustangs.
I like to think of the Mustang as being between a Gibson and a Strat: shorter scale, strat electronics. Because of the slightly mellower sound from the shorter scale, you won't get the icepicky highs people complain about with Strat bridge pickups, and you'll get a heavier sound than a typical strat in any position.
The trem is one of my favorite things about the Mustang, because they stay in tune nicely and if set up properly have enough range to slack the strings and come back in tune. They're also really, really smooth and easy in terms of action, very sensitive to moving the arm.
Switching is accomplished this way:
-if a switch is in the middle, it's corresponding pickup is off.
-if it is to the right or left, it is on.
-if both switches are facing opposite directions, then the pickups are out of phase.
You get used to this fairly quickly and can eventually make quick changes with a pinching motion of the fingers between the two switches.
IMO the Mustang is my second favorite Fender, I like the trem and the nice, heavy tones you can get from them, but overall I like the chime, sparkle, and hollowish tones from a Jag better.
If your Mustang doesn't look like this, be careful, it might not be a Mustang

(this is mine, on the right). A bunch of mostly original 66 parts that I rebuilt, has Duncan APS's.
HISTORY:
...As for history, uhh... Kurt Cobain used them? So does Shakira? They're big in Japan?
The Mustang was an outgrowth of the Duo Sonic/Musicmaster line introduced in 1957, in 64 or so they revamped that line with optional 24" scale necks (as opposed to 22.25, which are also found on some Mustangs, but eventually discontinued), with offset bodies, different switching and pickup placement, different bridges etc. The Mustang is a "deluxe" Duo Sonic, with one of the best trems Fender ever made, rather than the Tele style 3 saddle bridge. They were initially slab bodies, but recieved contours in... 67/8 or so? Duos and MMs never got contours. But most people find the Mustang body thin enough to not really need them anyway. They were the last guitar introduced during pre-CBS Fender, and the last of the "weird" Fenders to get discontinued (in 1980 or so). Also, they were the first to be reissued (in 1984) by Fender Japan.
The comp. stripe ones, like you have, were initially produced between 69 and 72, in orange/red, red/white, and blue/light blue. The first few have matching headstocks, then CBS got retarded and couldn't be arsed to do that after a couple years. The final models (late 70s/early 80s) are usually black or wine red with black guards and pups, or bare-ashed.
They also made the Fender Bronco, which is basically a single bridge pickup guitar with a trem entirely different than a Mustangs.
The Cyclone (which hopefully you didn't accidentally buy) came in 3 variations; standard, II, and HH. A Standard Cyclone has a bridge bucker and neck single, with a strat bridge and 24.75" scale, with a Strat thickness body. A Cyclone II is that, with 3 Jag single coils, a Jag switching plate, and a stripe. The HH is as predicted.