which meal & where will you be? You've got 2 Epcot World Showcase restaurants & a Magic Kingdom resort restaurant. If it's for lunch...choose your restaurant based on where you're at so as not to waste too much time traveling in the middle of your day.
If you're going to be in Epcot during lunch or dinner that day, then I'd say San Angel first choice, Les Chefs a close second (we liked both...but the atmosphere at San Angel beats the bright/crowded/noisy Les Chefs anyday) If you want the Remy-rat visit, of course you better choose Les Chefs.
If you're at Epcot, it's kind of a convoluted pain to get to Grand Flor...either take a bus to GF or take the Epcot monorail to TTC & then switch to the Resort monorail. Sounds easy, but the bus will take you 30-40 min + the walk-time to get to the bus stops. The monorail will take you 30-60 min + the walk-time to get through Epcot to the monorail. So, though we really enjoyed our Grand Flor Cafe meal, I would not recommend eating there unless you're staying at one of the monorail resorts...or you're at Magic Kingdom that day or evening. Then it's more convenient to hop the resort monorail from MK and eat at a MK resort restaurant.