I am absolutely certain you did not see an Orange AD200 in any live performance videos from the 70s. Orange had a pretty troubled history, and the current version of the company did not come into existence until the late 90s. The AD series amps were developed by the current company, and although they may look similar to the old amps, the AD200B sounds more like a vintage Fender than a vintage OR200.
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Some call these old Orange heads Ormats. This is an OR200.
AFAIK, all of the OR200s were made by Matamp and are extremely closely related to the vintage Matamp GT200. The early amps had James tone stacks and put out a bit more than 200W clean. The AD200B tone stack is pretty much a direct copy of a Fender tone stack, although the component values are a bit different. Also the AD200B only makes about 165-170W clean. It sound fabulous as long as you don't run really heavy bass. If you crank up the bass too much, the amp tends to lose focus and mush out at fairly low volume.
I own an AD200B and I think it is a fabulous sounding amp and have written quite a few posts here on Talkbass. IMHO if you max out the (master) Volume control it sounds and behaves more like a big blackface Fender Showman than any other amp I have played. However if you dial the Volume back and crank of the Gain control, the preamp quickly transitions into OD. A lot of people complain this occurs much too quickly. I learned to play on a blackface Fender Twin so I really like the AD200B (it feels like home), and 170W is a nice amount of power.
My SVTs are noticeably louder and have a different voice. Their frequency response is actually flatter, but I think some people will have the perception that the AD200B is a bit more HiFi because it scoops out some of the mid range frequencies that you may not want to hear. This is not good or bad, it's just different. You can't make an SVT sound like an AD200B and you can't make an AD200B sound like an SVT. Nothing wrong with having both IMHO...or choose the one you like best.
For the record I also own a vintage Matamp GT120 which is fairly closely related to their old GT200s and the old Orange OR200s. I don't really think my AD200B and GT120 sound very similar.
AFAIK there is plenty of love for the AD200B. There is also a fair amount of criticism. IMHO try it out and form your own opinion.