A Slingbox with motorized FTA works fine. Just have to be patient with the learning and executing the remote control commands. If you have a working system though, its just like sitting at home. I'm not familiar with the HD quality though, as all of my Slingboxes are of the classic (SD) variety. If you can get yourself a Slingcatcher box (Another great sling product, discontinued in US, but generally available for around $250 on Amazon via the UK) you can watch your Slingbox FTA setup remotely on a TV, and the SC's streaming quality is almost like you're at home if the broadband connection is nice enough.
FTA receivers are generally not supported by the default Slingbox remote codes that come with SlingPlayer. Most popular FTA remotes (code files) can be found on JP-1 related forums or other places on the web. You can also try making your own custom remote control codes (not recommended, but an option if your a techie.)
I will say it's not too fun actually setting up (or resetting) your saved motor positions over Slingbox, but it's possible. You have to have about five times as much patience with doing that. I've been stuck at the office on Saturdays and had to retune the motor to pull in a college game properly.
Hope this helps!