Re: The Fender option
fender tweed bassman - its what Jim Marshall based his earliest designs on including the JTM45 that eric clapton used on Bluesbreakers, or even the JTM45 head used extensively by none other than Jimi Hendrix.
Fender amps are not "twangy" although a lot of recordings where people use telecasters may be where you get that idea. They are more a full range of sound, big bass as well as tops. The old ones were designed by a man who did not even like distortion, its just that guitarsists kinda found out how cool it was and kept turning things up. SO its not the amps that sound twangy, its the guitars and the way the eq is set. You can get a titanic amount of bass out of a twin or even out of the samller 6v6 based amps.
FWIW:
I have a jcm900 master volume 1x12 combo which i would love to sit on top of a 1912. I aslso used to use a jcm900 dual reverb half stack many years ago as my main gigging amp. Both of these marshalls in comparison to most fenders i would say have waaay less bass, but more gain, compression and definition at higher gain settings. The clean channel on the dual reverbs is pretty lame, but the crunch channel works well. Fender amps will give you a bigger cleaner, more inspiring tone if clean (maybe with a hint of breakup) is what you are after - think Stevie Ray or Buddy GUy. JCM 900s come freom the era of hair metal. They do screamong high gain well - as long as the masters are turned up - but they are not really responsive the way a fender would be. When i say fender im talking very broadly - because there are a huge amount of different fenders out there.
However - if you are looking at a marshall 900 and you want less of the hairspray and more organic feel, then make sure its a master volume model rather than a dual reverb. Set for clean (or as close as you can get) master on 6 or more and a drive pedal, these things are rock monsters.
Im not sure what boogie you have but they generally lean towards a more modern sound - huge bass. massive saturation and a clean channel that is pristine. Fender cleans are usually spongier and warmer, whereas mashall dirties are a more mid oriented growl. I generally prefer fender cleans over boogies and marshall dirties over boogies. However - no amp co do everything.
Still if i had to choose fender or marshall and could only have one it would be fender any day of the week.