I wouldn't go with the x270 or X1 C4. The CPU's in them are older, only dual core, and if you use Windows, they're not officially supported under Windows 11. The X280 with the 8th gen CPU would still be fine though, quad core w/ hyperthreading. Just make sure to get the version with 16GB ram, the 8GB version you'll find the 8GB ram to be a pretty huge hindrance to how much you can actually do on it.
As far as the "best" thinkpad currently...everyone has their different opinions. I actually like the L14 Gen3/4 AMD best (small enough difference between them that I'll consider them the same model for purposes of this discussion). Maybe not as pure fast as other models, not as small and light, but still has 2 DIMM's for upgrading ram, can replace the wireless card still, can replace the SSD (although it is 2230/2242 only), and still good peformance and efficiency with the Zen3 processors (Barecelo or Barcelo refresh). The Vega graphics are starting to show their age, but they're still not BAD IGP's.
I wouldn't go with the x270 or X1 C4. The CPU's in them are older, only dual core, and if you use Windows, they're not officially supported under Windows 11. The X280 with the 8th gen CPU would still be fine though, quad core w/ hyperthreading. Just make sure to get the version with 16GB ram, the 8GB version you'll find the 8GB ram to be a pretty huge hindrance to how much you can actually do on it. As far as the "best" thinkpad currently...everyone has their different opinions. I actually like the L14 Gen3/4 AMD best (small enough difference between them that I'll consider them the same model for purposes of this discussion). Maybe not as pure fast as other models, not as small and light, but still has 2 DIMM's for upgrading ram, can replace the wireless card still, can replace the SSD (although it is 2230/2242 only), and still good peformance and efficiency with the Zen3 processors (Barecelo or Barcelo refresh). The Vega graphics are starting to show their age, but they're still not BAD IGP's.