Received the Sony Ericsson X10 this morning. Beautiful screen, a lot larger than the LG model, but feels like it weighs the same. Running Android 1.6 and from what I was told in a private list Sony Ericsson is not coming with an update until later in the year (think September 2010). Like the LG is uses Moxier to synchronise to Exchange, which is a pain since it does not share contacts with the dialer and messaging application. So only really good if you sync to Google Apps.
GPS is solid, configuration very easy, the on screen keyboard is responsive and keys well apart to avoid typos. Working through it later.