I do agree that the X230 without upgrades is a bit on the slow side. It is usable but somewhat limited and also loud sometimes (at least mine). I still like it because in the machine there is the classic keyboard installed.
On the other hand an upgraded T430 feels just right to me. Wanted to buy a 3840qm CPU but it works fine with a 3720qm. I do not have the double-pipe fan, but it is still ok so far. In my eyes the real weak part of this machine is the original display, which can be upgraded to an IPS one.
Here are some details on how to upgrade such a machine. Having a really good T430 requires some new parts (display, lcd controller board kit, new cpu, good ssd, max ram, delta fan and a classic keyboard for dedicated users) and work=knowledge (flashing the bios requires taking apart the machine as the chip is on the back side of the mainboard). If someone prefers to save all that work/time/hassle (and spend a bit more), a newer (more silent, lighter, better screen, more ram) machine might be a better option.