Re: Fender Jazzmaster, Mustang, Duo Sonic, and Jaguar guitars
	
		
	
	
		
		
			Mustang pickups are exactly the same as Strat pickups, except without magnet stagger since they have closed covers. The reason for the closed covers is so when switched out of phase you won’t get hum touching the magnets.
		
		
	 
To be specific - even non-staggered Strat pickups are different from Mustang pickups, which (except for very late plastic-bobbin examples) have pole pieces flush with the bobbin rather than slightly elevated as on a Strat.
I think one part of the offset equation that really affected their use in surf music was the vibrato - Set to float with up/down-bend, the Jaguar/Jazzmaster vibrato has close to the same range as a Strat vibrato but provides much more subtle/less direct control over its entire range of motion. The Mustang vibrato is almost the opposite - gigantic range and a very direct yet loose feel. Jaguar/Jazzmaster vibratos are easy/plug and play, but getting Mustangs to work properly can involve a lengthy setup and lots of patience; there are a lot of parts that need to be balanced properly to each other and the pivot points cannot be worn at all. That said, I really love the Mustang vibrato - probably the worst thing about it to me is the giant tailpiece cigar can get in the way of your picking hand.
I think yet another reason these guitars were picked up for surf (Jaguar/Jazzmaster in particular) are the 1 meg pots they use. I don't think 1 meg makes as earth-shattering of a difference as some people do, but they're notably brighter than say a Strat. You will probably want to totally re-EQ your rig around the guitars. Speaking of the wiring, the Jaguar has a "bright" switch that works on both pickups and indeed can sound very (stereotypically) surfy. Elaborating on the Jaguar's wiring - basically the three switches on the treble bout are: Neck Pickup On/Off, Bridge Pickup On/Off, Brightness On/Off. The switch on the bass bout puts you in 'dark' mode (Fender calls this 'rhythm' mode) and activates the neck pickup only with a 50k tone pot and its own separate volume/tone rollers. The intended use is to have a darker tone dialed in that you can switch to at any time, regardless of the position of the switches & knobs in standard/'lead' mode. A Jazzmaster has the same circuit, but uses a 3 position switch similar to a Gibson SG and doesn't have a bright switch.
Figuring I might as well keep going since the Mustang was already pretty well covered above... Jazzmaster pickups sound somewhat 'cooler' and 'darker' if that makes sense; smoother and fatter than Strat pickups, but without as much twang. They are also more susceptible to noise than a lot of other single coils, is what I've noticed. Fender 'fixed' that problem with the Jaguar pickups, which are really very well shielded thanks to the presence of the claw; if you look at the patent diagram their function is really very similar to the design of Lace Sensors, although with not as thorough implementation. So to me they are notably quieter than a lot of single coils - although much of that depends on the shielding in the rest of the guitar. However, the claw around the Jaguar pickups can also cause some microphonics at high volumes. Jaguar pickups have slight differences in the size of the bobbin vs. Strat pickups but don't sound too different on their own. The Jaguar's 24" scale possibly also adds to the twanginess of the guitar - my overall understanding is that after the Jazzmaster was recognized as appealing to surf guitarists, Fender produced the Jaguar specifically with surf in mind.
Anyway you can tell I'm about as big of a fan as any of those guitars have - almost certainly so on this board (specifically for the Mustang.) IMO the Jaguar has one of the best clean tones you can get, and nothing sounds like a Jazzmaster. I like Mustangs but am more hesitant to recommend them to someone who is not already comfortable with the vibrato (both in operation and setup) since the Mustang sound is not as unique as either of the other guitars; almost might as well get a Strat. My parting note - if you get an MIJ/CIJ or Squier Offset, 
EXPECT TO REPLACE EVERYTHING. The MIM and US-made guitars are MUCH better all around.