I've had my Lenovo Thinkpad X1 Carbon for almost exactly a year now so I thought I post a quick follow-up to the original entry I posted last year.
First, the keyboard. Within a matter of hours using the original keyboard the enter key started sticking. A new keyboard was ordered and installed and I've had zero issues with it since. I didn't originally think I would like the X1's keyboard due to the separated key layout but I have to admit I love it. I find it very easy to use with just the right amount of tactile feedback for my tastes. It appears my original keyboard troubles were due to a single defective device and not something endemic in the design. Whew!
The exclusion of an RJ-45 network port still bothers me a little but it hasn't been a major factor. I still prefer a hard connection when available but the Wi-Fi performance has been exemplary so I can give that a pass.
The lack of an on-board DVD ROM drive has been a non-issue...so far. As I'd said in my original post I rarely find myself in need of such a drive but when that need arises I fully expect to be cursing the fact that I left my external drive somewhere other than where I'm at. Still, I'm happy to trade the convenience of an on-board drive for the loss of its weight and bulk.
The port replicator is probably my biggest single issue with the X1. I had a number of display driver and minor stability issues early on though driver updates over the last few months have improved it dramatically. I'd much prefer a traditional docking station but after I've plugged in both the port replicator and external power cable I rarely notice the difference anymore.
Battery life has, up to this point, been pretty good. When I first got my X1 I could work disconnected for about 5 1/2 hours. Over the last year that has decreased to around 4 hours. That's still generally enough time to suit my needs but the trend downward has me concerned. Past experience with laptop batteries has shown me that it may go from the lifetime I have now to less than an hour very rapidly. I'm hoping that trend doesn't start too soon though because I've been told that a new battery will require sending the machine back to the factory. If that's true it's going to be very problematic. I'm crossing my fingers that it stays at current levels for a while yet.