Hi. I'm afraid I can't comment on X10 'cause I don't have it (yet!). As to your other questions -
I have fully tested the TSU7000 with all my kit and have had no problems at all. The only issue I did have is that my Panasonic TV would not respond to any of the inbuilt code sets but I expected this would happen as obviously the inbuilt IR is for the US market. No problem of course, I just learned the codes instead.
Like you I previously owned an RU890 and all I can say is you have to see the TSU7000 to believe the difference! One of the best things for me is that you don't have to constantly adjust the brightness. It remains perfectly as set.
I bought mine from BlueDo.com and I honestly couldn't fault them. I've bought things from UK based web sites that have taken longer to arrive! I would strongly recommend you ask them to declare the remote as a gift with a low value, that way the import tax is minimal.
In summary, I'm sure you won't be disapointed if you do buy the TSU7000 whether you choose to buy from the US or the UK. It's such a step up from the RU890 in all areas. Even ProntoPro Edit NG is better, not perfect but better! Hope this helps, best of luck.
