Their careers are comparable to a certain extent... They broke into the business around the same time. Flair became NWA champion in '81, while Jumbo became the ace of AJPW in '83. Obviously, Flair worked the territories and traveled more, but Jumbo worked against most of the big names who toured Japan. All Japan was often in the position that Crockett was in regarding the popularity of Hogan/WWF and Inoki/NJPW. Jumbo/Tenryu is comparable to Flair/Steamboat. Jumbo vs. Misawa & Co. is comparable to Flair vs. Sting and Luger... In terms of differences, Jumbo's reigns as NWA International Heavyweight Championship and AWA champion, while considered prestigious in Japan, were not as highly regarded as the NWA World Heavyweight championship, which Baba had won... There was even kayfabe reasoning why Japanese wrestlers couldn't beat touring US champions... Jumbo never jumped to NJPW like Flair going to the WWF, likewise no major star jumped to Crockett like Choshu jumping to AJPW (not with the same impact)... On the flipside, Jumbo went into "enemy" territory for a 1990 Dome Show and was so over that he was declared the ace of all Japanese wrestling, which is a type of status Flair didn't have outside the territories and hardcore fans. Japan is a much smaller "territory", however. Baba also moved away from traditional US style booking towards something that loosely translates as King's Road craftsmanship, a new style of wrestling that Baba deemed necessary given the death of the territories and decline in touring American wrestlers. The comparison ends with Jumbo's illness.
Outside of comparing their work, matches and patterns in their careers, we're a lot more privy to the inside working of the US business. What we know about Jumbo is probably less than 10% of what Japanese people might know. I've never read Dave's obit for Jumbo, but I'm curious about how much information is in it.