I knew about the RAM but the difference is still significant. In the X1 your max is 16GB and only if you decide on that upfront. On the T460s you can go up to 20GB at any time. Didn't know about the SSD, thought it was soldered on, thanks for the correction.
- The T460s (and T470s) only has one free RAM slot, the other is soldered on as well.
- You're implying that the X1 has a soldered on SSD, but that's not true, it has a standard M.2 connector for the SSD. Maybe you were thinking about the MacBook...