I think it may be a software issue. I have a great signal at work, all bars lit, then suddenly it will say there is no network. At my house 3g has never been great but it seems pretty good on the X when my last phone would rarely get it. Same thing happens, bars drop and it seems to hang.
The airplane mode "trick" sometimes seems to help. (Just turning airplane mode on them off for the person who wa asking) This is why I think it's a software issue, like it drops 3g when it's not being used to save battery maybe? Then hanging before the 3g kicks in again.
Last night and so far today it's been worse than ever before.