Share your experience!
Yeah, I had the same problem when I bought my Xperia L (3 weeks ago) and it was a huge pain, but recently the 4.2.2 update has been released which (for me) significantly improved touch sensivity and now it is working a lot better (not perfect)- but still good.
Try upgrading to 4.2.2 via SUS. Then via SUS carry out a firmware repair to re-install a clean 4.2.2 so any issues are ironed out.