I had a booster at the old apartment (I had cable internet and three TVs all splitting off one line coming in with a fairly weak signal to begin with). The signal's a lot stronger at the place I'm at now.
The bummer with the booster is that if the power goes out, so does the cable... and considering I've got the cable modem and the wireless router plugged into the battery backup, which along with the main computer and main monitor use up all the battery backup plugs, that could be a major bummer.