For the most part, hyphens devalue the name. There are a few exceptions but even than it's usually a coin flip or a matter of personal taste. ie an argument could be made for both sides w/ above example. Tweaking the casing used in displaying the name can help seperate out troublesome connections similar to what hyphen achieves in above example. Ngage or n-gage?
IMO, hyphen improves 24-7: 24-7info or 247info, but it's still a coin flip. Wi-fi is almost always w/ hyphen in print, but wifi would be the preferred choice for a domain name.
Much of this issue revolves around the particular categories of terms that either don't read well, don't sound right, or don't "describe" well. Getting 2 out of 3 right, (given all other factors ie word quality are there), will usually mean an averege name w/ a shot at being good, but not VG or great.:gl: