Yeah, they're quite different animals, especially when you get into early-70's Greco TL models.
Tokai didn't start making copy guitars in any meaningful numbers until late 1977, and their Tele copies don't hit the catalogs until 1981, so if you compare say a 1974 Greco TL with an '81 Tokai TE, they reflect the development of the Japanese guitar industry as a whole as much or more as any differences between the brands. The older guitar will be a lot less accurate copy and primitive in other ways too. Might still be a good guitar, but if you want copy accuracy you need to look at 1980-82 Grecos, (and I personally don't usually bother with guitars made before 1976, of any brand). Greco Fender copies disappear around April '82, when brand owners Kanda Shokai and Fujigen (the manufacturer) become partners in Fender Japan, so there are no later ones.
Comparing a 1981 Greco TL500 and a Tokai TE50, both are accurate copies of 70's Teles with six-saddle bridges, those I've had have been excellent and looked and played pretty similar. There is a difference in tone, and imo, the Greco is superior on that count. The Gotoh pickups in Tokais are good, but I prefer the Maxons (or Maxon-derived, by 1981, Fujigen had taken over Maxon's pickups operations themselves) in the Grecos. ; Also, in the case of Tele copies, most Tokais have 1 meg pots, not the usual 250k you'd expect in a Tele. Apparently, Fender did use 1 megs in Teles at some point during the 70's, but copying that feature was A Bad Idea, In my experience, Tokai Teles can get pretty icepicky at times. Easily replaced parts though.
When it comes to higher models, I have no personal experience beyond TE60 and TL500. By all accounts, Tokai TE80's and higher are superb, which I can easily believe. The Greco equivalent would be the 1980-82 TL800 Super Real, a super-accurate Nocaster copy, rare as hens' teeth and really expensive when they do turn up (which goes for high-end Tokais as well). Otherwise, the TL500 was the only Greco classic Tele-style guitar for many years.
The problem with either is finding them. It's pretty obvious that the Tele in its original config was by far the least popular of the US classics in Japan. You simply don't see that many for sale these days. Oddly, copies of the Telecaster Thinline Deluxe is almost as common. I guess some local rockstar played them, but I haven't been able to figure out who.
Either way, both are fine Teles, with the Grecos having a slight edge in my experience. A Tokai might actually be slightly easier to find than a later Greco. Greco was a non-export domestic Japanese brand, so all you find outside Japan these days are recent imports. Tokais were sold new in the West, so there should be more of them around.