I've been using an SB Live! Platinum ever since it first came out, and I've had absolutely no trouble with it. It sounds like the people who are complaining about the Live! cards are having trouble with the 5.1 versions, which have built-in Dolby 5.1 decoding. This is not necessary unless you're watching DVDs and using 5.1 speakers that don't already have Dolby decoding, which is a rare scenario.
As for the differences between the Value and the X-Gamer, the only difference lies in the software bundle. There does happen to be a SB Live! X-Gamer 5.1, but again, unless you have a 5.1 set of speakers that doesn't already have built-in Dolby 5.1 decoding, you'll want the regular version of the card, not the 5.1 version. The Value is usually cheaper than the X-Gamer, and the only difference is that the X-Gamer comes with some games. The Value doesn't have much of a software bundle to speak of. Physically, they're the exact same card.