I've caught gar and bowfin both on white spinner baits before. Lot of fun, but I hate to have to get them off. That one in the picture isn't very large either. A good 3 foot one will give you a heck of a fight. I've seen one almost as long as my 2 man pirogue out of Toledo Bend in LA...might have gone 6 feet. According to wikipedia, the current world record is 279 lbs.
As for eating them, some people do, but the only thing I've ever heard of is gar balls. Just as an FYI, I looked it up and found a recipe for them. Here's the link. Can't say I'll ever try it, but someone out there might.
Cajun and Louisiana and Cajun Recipe Page - Cajun and Creole Louisiana Recipes on The Louisiana Website Directory - Cajun and Louisiana Website Directory
Anyway, hope that helps the curious. If anyone's ever tried the gar balls, let me know how they are. I've always been curious, but not enough to try them.