They're pretty good. They can be expensive, though.
Personally, I like OTB Desertlites (Or Junglelites, depending on your area). They're made by New Balance, so don't be alarmed if you find them under that brand name. They're light and comfy, and padded without being overly padded. Prices are about $120-$140 shipped
Half my battalion seems to have Nike SFBs. They're in the same price bracket, but smaller, and less traditional looking. There's little padding, but they're minimalist boots designed to be lightweight, and let you feel the earth. The sole wears out more quickly than issue boots.
Very similar to the Nike SFB is Bates's new "Zero Mass" line seems like a mix of the Desertlite and SFB. More traditional look, but still a super lightweight boot.
If you have any questions, feel free to PM me. I've got some experience on the matter.
EDIT: Another important thing is to try the boots on before you buy them. I've gotten lucky ordering boots online a couple times, but the sizing can change from company to company. If the boots are a poor fit, you'll get blisters, which won't be fun. Bad boots will be a constant source of frustration.