Probably the amp I gigged most with, over the last 10 yrs of playing out. They are great amps, and if anyone says they are 'thin' sounding then they are not setting it up correctly.
You HAVE to run the gain above 6, as well as either the Output Master or Lead Master above 6 as well. That is an absolute MUST. If you don't, you're kneecapping the amp from the start. It will only sound thin/less ballsy if you set any of those lower. The Jubilee also has, by far, the BEST EQ response of ANY Marshall, ever. They are darker than a superlead or 800 but can be dialed in bright enough. They are also the only Marshall that likes ANY version of a V30, as well as the usual suspects ie GBs, 65s, 75s.....
I've had 10 originals from 87-89, the best value are the black tolex versions from 88-89 since they will have the final preamp circuit revision that appeared around serial #3000 or so in 87. The earlier pre circuit amps are still great, but have a touch less gain and low end available.
I've had 1 2555x, and while I agree with Tiago in that the originals are better I found that the reissue is damn close in a direct A/B comparison, the 87 2555 I had won that contest at high volume with the vintage Dagnalls but not by much. The reissue is absolutely a killer amp. The Slash from 96 is also great and has even more low end than any other version.
The super cool thing about the reissue 2555x is, you can use any 2 pairs or quads of octal tubes you want in the power section. 2 EL34s with 2 6550s, 4 6L6, 2 KT88s with 2 6L6, KT90s, etc etc. THAT is a very cool thing and can really change your tone up however you want it.