I very nearly got a T42p, because I could get a bigger screen, blah blah blah ... a fancy T42p for about the price of a good T43. But.... A difficult sticking point for me was that I wanted a Bluetooth CDC in it, and getting an antenna-equipped model and finding a CDC from a third party seemed dicey. Also, some of the new T43s have a PCI-X Radeon video card and faster (PC-4200) DDR memory. So I got what I got.
After 2-3 weeks with it (and yes, it did take within the 2-4 weeks they specified, though the projected delivery date was going to be 8 weeks after I ordered

probably due to demand, as I didn't order any mods or upgrades), I'm perfectly satisfied. Your mileage may vary, but I have NO noise or heat problems. Partly because - ahem - I use the included power control utility that lets you set performance and power consumption and - yes - fan volume, partly because it just may be a slightly better MTM than what other people got. My Dock II is the desktop leaf blower, so I don't mind the mild noise that the laptop's fan makes from time to time when plugged in and set for max performance.
I CAN tell you that if you are patient, and are convinced that a Thinkpad is what you want, I think you will get value. The software shipping on T4xs is exemplary, tons of security and backup and utility out of the box. If you get a CD or DVD writer, get discs, and make your Rescue and Recovery discs immediately. I did, and even used them after messing around with some settings. Right off, you do NOT have to get special backup software, CD/DVD burning software, multimedia widgets, etc., etc. It comes equipped, period. Warranty service was good (I had to have the LCD replaced; unusual but not unheard of).
It's just head and shoulders and torso above the Dells and Toshibas I see these days.
Noise ... you can try various power setting and make up your mind.
Heat ... it can get warm, but I use a Targus Coolpad (
http://tinyurl.com/8wu9a, an Associates link to Amazon). For the price of a keyboard wrist rest, it will keep your T4x clean (off the dirty library/cafe table), cool, and canted at a more comfortable angle. Bottom-case heat worries solved for < $15.
Other people's experiences aren't necessarily less valid or more so than mine ... it's all anecdotal. At the end of the day, read some reviews, Consumer Reports info, and make up your own mind. My two cents, I wouldn't make a laptop choice based on which got shipped first. I chose quality, and I think I got it.