El Jalapeno is a great upgrade from the previous establishment and I'm glad to see another very good authentic Mexican restaurant in Madison. Prices are completely reasonable, salsa is quite tasty, and the food is right on par with Taqueria Guadalajara in my opinion.
What's really surprising is that this isn't a hole in the wall once you actually walk into the place despite how the former establishment was and how the outside of complex looks. They have some TVs, a colorful atmosphere, a good amount of seating, and very friendly staff.
Their gorditas are the go-to favorite for both my wife and I, and their tacos and chimichangas are also top notch.
Madison is very hit or miss with Mexican from what I've experienced (and I've tried a decent amount of places on both sides of town), so make sure to get to El Jalapeno if you're a fan of food from south of the border. It's not the best I've ever had, but it's right on par with the best of Madison.