We (as my family and I) have had 2 Lenovo tablets, an X61 Tablet and an X201t with extended batteries.
We have had the X61 Tablet since around 2007. It was a little slower than the rest of the laptops (not tablets) with the same specs but it worked great. The best thing was the 4:3 display with 1400x1050 on a 12''. This display is not built anymore. It was very comfortable to work with and I used it to code and to take notes. Overall, it's a great machine. It's solid too. My brother was using it everyday until recently. Now his business partner is using it and they love it. They are Dr. and they use it to fill charts and write notes when meeting patients.
My brother has a X201t now. He likes it a lot as well. As you can imagine it's way faster, very snappy and responsive. He complains about the resolution though. The display doesn't have as much real estate. That's his only complaint. It is a little ligther than the X61 Tablet even with the extended battery.
Both pen interfaces are WACOM. They are very very good, very precise after calibration. These are resistive tecnology. Very different from touch screen phones. Resistive technology has some quirks but, IMHO, it's more precise than capacitive technology. Taking notes on a resistive technology is a pleasure. OTOH, notetaking on a capacitive screen is a PIA.