How different T and R series

I know that the newer T series laptops have better specs (CPU, GPU...) than the newer R series. There's no firewire port on T41 and further models.

The R series is aimed more at entry level users. It offers the chunkier ultrabay (12.7 mm height) hot swapable drive bay, and weaker gpu options than its T counterpart.

The T series are aimed at mobile professionals, especially the new t43 trim with its integrated fingerprint scanner and "sudden drop" detecting hard drives.

I currently have a t40 and its treated me really really well, and I abuse the hell out of this rig.

The predesktop area is nice.
swappable drives for batteries, or second hard drives is sweet, but here are the major flaws I find.

Only two usb ports.
No firewire
lack of media card support
adding bluetooth also adds like 600 bucks.

if you're poor, go with the r series, if you have some disposable cash get the T, but always always always opt for the higher capacity 9 cell battery, you'll thank me later.