Based on leaks and your needs, the 1700x seems like the cpu for people who don't want to manually overclock their cpu with the extended range. From the couple leaks that have been released, the extended range is based on cooling solution which should give +100-200 mhz which might translate to a couple seconds/minutes quicker on complex renderings and video processing.
I myself am looking at the base 1700 because I'm usually ok overclocking myself but usually only do that after the CPU is out of warranty. I do light video editing and some streaming but beyond that, just games.
If you want to wait for official reviews, you'll have to wait until March 2nd, which is 2 days away. Not too long now.
Edit: I'm also waiting until March 7th since the Motherboard that I'm looking at isn't coming out until then.