i can't comment on the T430, so this is not technically an answer to your question. but i ( >>76
) have a t410 (with 8g RAM) and I absolutely adore it. it very quickly became my daily driver, replacing a laptop with far better specs. This is primarily due to how much more natural and comfortable it is to interact with this machine: the keyboard has a very pleasing about of physical feedback; the use of a docking station means that this laptop functions happily as a desktop as it does as a laptop; the clitoris
pointing stick, though initially awkward, is far more ergonomic and natural; this thing's tough a brick (which is extremely important given that i am a natural at stress testing) - just to name a few things.
granted, there are definitely some issues with it. as my quoted post said, this thing overheats significantly - ie, often not safe for lap; generally warm if not uncomfortably hot on the face plate; has shut down from crit temps 4 times in past few days (granted, the ambient temperature here is definitely not helping.) It also took a fair amount of configuration with the Arch setup to get things running smoothly (ie, setting up individual keybindings for things like volume or function buttons; getting the computer to wake from sleep without restarting, etc, etc) but it's been super worth it. depending on your usecase, the 420 or 430 may be more appropriate for you. but if you're looking for a durable, comfy, and decent laptop on the cheap, i think you'll find the T410 worth the money.