Ok - had my X121e with i3-2375m for 2 days now and here is the initial feedback.
Just to put things in context and give an idea of my point of reference: I have been a longtime Thinkpad fan after first using a T20 many years ago at work. I have owned a T40, Z60 and more recently a T400.
My current T400 is used mainly as a desktop device - via a Advanced mini dock and external keyboard, mouse and monitor.
I was recently looking to buy a Tablet PC so that I could view my collection of 720p and 1080 mkv movies etc around the house without hogging the TV screen. However, I found that none of the current crop of Tablets can play a High profile mkv files reliably and so decided that a reasonably powerful netbook would fit the bill.
This is where the X121e comes in...
I purchased mine from the UK Lenovo website for £349 with a 6 cell battery and 2GB RAM. I then upgraded to 8GB using Crucial RAM - which was an absolute doddle - no palmrest removal nonsense. Just pop 3 screws on the back and you are in.
Opinion so far:
Build quality seems excellent for the price. Lid is solid with rubberised covering, applying pressure on lid does not appear to affect the LCD display. LCD Display is much brighter than my T400. I miss the locking clasp on the lid - it was good to know the screen was locked in place when transporting the T400.
Never used a Scrabble tile keyboard before but this one the X121e seems perfectly fine. For me it provides as good a typing experience as the standard T400 in terms of tactile feedback etc. Obviously the smaller keys and subtle layout changes will have an negative impact - but they have done good job given the reduced surface area.
I miss the volume keys and the Fn+F12 for Hibernate of the T400. The X121e requires you to use the FN for volume, mic, brightness etc. and their is no Hibernate function key.
I miss the fact there is no docking station option - my T400 was docked and so all the cables were tucked away at the back. Now they stick out of the sides and make the desk look ugly and untidy. Even the power connector is on the side - yuck. Also, I find the 3 USB ports limiting - have had to replace my individual wireless keyboard + mouse with a single desktop set to leave 2 ports free.
One positive is the X121e has a powered USB port - so even if the laptop is switched off I can continue to charge a phone etc.
I used the DVD drive on the T400 so rarely that I dont imagine I will miss it. I have purchased a cheap USB Samsung DVD writer to create the Recover disks and any other occasional use.
I was concerned about replacing a 2.2Ghz Core2Duo with a 1.3ghz i3 - but my limited experience so far seems to suggest that the i3 is faster than the Core2Duo. e.g. had a quick bash on Lightroom 3 and it seems slightly more responsive on the X121e. Also, playing a 1080p 24fps mkv file whilst transferring a several GB of files from a USB drive in the background worked well.
The T400 card reader was spring loaded allowed you to push the card right in and further push to release. On the X121e the card sticks out and makes it feel a bit cheap.
One big positive of the X121e is the HDMI port - hurrah - at last. I could never understand why the T400 did not have a DVI port as standard and you had to buy a dock to get a digital output!
The X121e fan is definitely noisier than the T400 - typing this reply I can hear the fan in the background. Not loud even to annoy but definitely there. With the T400 the fan would be silent for low CPU tasks such as surfing. When I ramp up the CPU load the fan definitely gets louder. Thanks to the hardware HD decoder, though, playing a 1080p 24fps file only uses 10% CPU and so the fan does not get any louder and so does not disturb the viewing experience. The built in speakers are okay to for a bit of movie watching.
Another negative of the X121e is the 7mm Hard drive. This means I wont be able to upgrade the HD until 7mm drives come down in price a bit.
One final minor negative of the X121e - the combined single headphone/mic socket means I will need to buy a new mic/headphone set.
Apologies for the rambling post - been fasting all day and brain is not up to normal state of operation - not that it would have helped much
Will hopefully post back later on once I have used it more....