Pros: Low cost, decent build (not the best), fairly good performance, improved battery, small footprint, light weight, light weight small power supply, great full size keyboard, classical lay out.

Cons: Lost some of the solid quality from the IBM days, and didn't improve on some obvious issues. battery does not latch on tightly, satin finish still easy to scratch, left corner (pcmcia) bends and clicks when held on - it's the natural place to grab on when you think about moving the thinkpad, the original amber light preserves night vision and avoids disturbing neighboring passengers, the new led is too bright,removing the ribs underneath the front makes it more difficult to hold, and the weight should have been reduced more drastically after so many generations over the x40 or the x240s. the power plug now sits on the back, and could get in the way if you place the notebook on your legs. the screen no longer closes with the click of a latch, although it works ok without one.

Overall Review: I still own a x40, upgraded with ssd, which really improve its performance for normal uses. The big drawback is the battery life - a little over 1 hr with good 4 cell batteries (the original slim version). The new x220 has significant performance improvements and a classic layout that just makes sense for the user. I've tried many notebooks, but the thinkpad still seems to have the best balance of cost/weight/functionality/performance even when it's not as well built as the past IBM branded ones... Although I didn't pay anything close to the original asking price. Some other notebooks close to the thinkpad's spec that I've tried: The HP's professional line is much more solidly built, but the battery latch was way too flimsy (just two tiny plastic hooks holds the battery), and it weighs over 4 lbs for a 12" screen notebook seemed excessive. The Panasonic is a sleeker, much lighter, less than 3lbs with dvd drive under the keyboard, better performing machine with an awesome battery - they've had it for years (an improved version of the lithium batteries) that does not have the steep degradation curve of Thinkpads', but at $3000, it is tough.

Pros: this one was built in April supposedly, with 0 cycles. It arrived with 85% full, i think i'll charge it up to 100 and then use the 40%80% routine to make it last.

Cons: none

Overall Review: T400's are heavy! nothing bad about this battery though. Panasonics of this size were around 4 lbs for years, with a new battery chemestry. Unfortunately it costs around double.