I consider the SL-1500MK2 superior to the 1200MK2 in every way.
The 1500 Mk II is nice, but the SL-1200 Mk II is much more bombproof and same sound quality. And simpler mechanically. I like both turntables and have owned both turntables. Neither gave me issues. I like manual tables best. But automation is nice for some people. And the SL-1500, SL-1600. and SL-1700 are very recommended, especially in Mk II livery for those who like great automatics. But some parts for them are getting difficult to find. But they are superbly made and reliable as a whole. I like them as second turntables.
Fellas... There was no 1500-1700 Technics series.
The sequences goes 1300-1500 (auto, semi, manual) and 1600-1800 (auto, semi, manual) for both the originals and MK2 series.
The 1600-1800 used a substantially similar motor, platter, and tonearm to the 1200 series, but on sprung plinths. The 1300-1500 series, while fine tables in their own right, were were built to be a less expensive alternative, and are a little chintzier all the way around.
I don't think there's a case to be made for any 1500 being superior to any 1200. The real comparison would be the 1800 vs. 1200. Unless you're a DJ who uses the sliding pitch control, I imagine it would be a very close contest.
Honestly, it's hard to go wrong with any table that starts with "Technics SL-" and is followed by a four digit number starting with 11 through 18. Pick based on availability, your budget, and the features you want.
The only models waving red flags would be the SL-1300MK2 and SL-1400MK2, which are prone to an internal gear cracking and taking out their auto functions. I've seen them repaired, but it's not an easy job.
I've had several - I currently have a 1700MK2 that needs a little work to get it back online. Eventually, I'd like to have another 1600 or, if I can ever stomach full manual, I'll bite the bullet and pick up the classic 1200MK2.
People running high-end tables tend to scoff at these mid-fi Technics direct drive decks, but I can't see ever seeking out anything else. Playing records on them makes me happy.