I would get a Slingcatcher from ebay.
98% of the time is the best thing that Sling ever made. 1.9% is frustrating (mainly due to the method of entering log on details etc). 0.1% says cannot connect due to network error (but a reboot usually clears this message).
But I understand these odds are much better than other devices!
Will work fine with pro, pro-hd, HDS-600RS etc. But I think will not work with the new 350/500 devices.
I got 3 slingcatchers. 98% of the time I am very happy with them
The slingcatcher (for me any way) was simple to set up. Plug it in, log in and way you go. It will not work with the newer slingboxes (350 and 500), but works great for the ProHD and earleir models. It'a a discontinued product so no updates forthcoming. A great feature is its ability to provide a smooth picture when the internet speed jumps around which it can sometimes from the UK to US. Getting one can be costly - ebay and others charging some insane prices. So you may wan to to look at say Roku or WD Live which you are - they are a lot cheaper. They provide a clearer picture but can have more difficulty with wildly varying speeds with at high picture setting (HD) leading to some skipping - more than on the catcher. If I were to do this all again I might look at the Roku given the slingcatcher prices. I use Boxee Box as an alternative that I beleive has the same platform as the Roku (although not quite the latest as Boxee Box too has been discontinued!).