I use a Slingbox Pro-HD with my Tivo Premiere to placeshift when I am on the road, oftentimes overseas. My home cable modem upload speed is about 1.5-2 Mbps, but often the gating factor is really the flaky download speeds at hotels or in other countries.
I use either the Slingplayer client on my Windows laptop, or mobile tablets like Nook Color, Nexus 7, or iPad. I don't expect HD quality due to the hotel connections, but if the connection is solid the quality is quite good. What I do like about the Sling players, compared to other things I've tried in the past (like free Orb streaming) is that the bandwidth will automatically compensate up or down. So sometimes you can still watch something at only 100 kbps, but if the congestion frees up it will ramp up the quality to use 1.5 Mbps or higher.
Since the Pro-HD does not have HDMI in/out, I connect it to the Tivo using the component pass-through connections, which then go to my TV. I also simultaneously placeshift "locally" by having the Tivo's HDMI output via a long cable to another TV in a different room in the house - however this means both rooms have to watch the same thing. I'm crossing my fingers that the upcoming Tivo Mini will support the Premiere and can replace the latter HDMI connection, so that I can steal a tuner to actually watch a different program in the other room than what's showing in the main room...