Here's what the article says on the JTM45 Reissue:
"While the reissue looked very similar to the ’65 on the outside, especially due to the fact that it’s already 20 years old, the differences on the inside were quite pronounced. Assembled with more modern methods, and using a PCB rather than hand-wired turrets, you could easily be fooled into thinking that it wouldn’t perform like the others. This particular amp was the only one in the bunch to use EL34s rather than KT66s or 6L6s, so the sound was definitely different. It was incredibly loud and focused sounding, and actually had many of the characteristics of a Super Lead. The sustain and power of the amp was incredible, and for an amp that can be found used for around $1000, this is a sleeper bargain. Marshall has taken some flak for their amps sounding stiff and cold from the factory, but with a little attention–slightly hotter bias and good tubes–this amp is a monster. And just because it says it’s a 45-watt amp, don’t harbor any illusions that it would be a good bedroom amp. This is a loud and powerful beast, and a tone machine as well."
Keep in mind that they tested a 1990 Reissue, which still sports the old Drake transformer, of which some say it's a great sounding transformer. Newer Reissues use whatever transformer, but they also sound extremely well. I personally,
couldn't detect any big difference.
I think Gary Moore played the entire 2Still Got The Blues" album on a 1990s Reissue :-)