Well...the show HAS legs, as it was just renewed for a third season. According to info published on TV ratings sites and by Food Network's press releases, Sandwich King is a hit, is either #1 or #2 of all FN Sunday morning to mid afternoon programs and usually has more viewers than Guy's Big Bite.
Also, this past week, Sandwich King got nominated for a Daytime Emmy award for Outstanding Culinary Program. It took Guy's Big Bite (which also got nominated this year for Best Cooking Show) 5 years and 11 seasons to get nominated. The director was previously nominated in 2009 for Best Director. It only took Jeff's Sandwich King his first season of six shows to get nominated.
Also, Jeff's getting his own primetime show on Food Network ($24 in 24 Hours) that premeires in August. He'll be the only FNS winner other than Guy to reach primetime status.
It's clear that, after Guy, Jeff's the most successful FNS winner and, while nobody will match Guy's rock star status, every winner has developed its own following and style, some with more success, extent and accomplishments than others.