After numerous visits pre-yelp career and they have always been A-OK in my book.
Service: 2 years ago it was kind of hit or miss, but the most recent visits into last year have been great. Servers were consistent with getting the orders in and drinks fresh. The times we ordered fresh guacamole at the table, it's always been made well with a smile. They kept their bottomless Chips and Salsa promise at the table.
Mexican eats: If you have time, get the table side guacamole that's made..wait for it.. table side. =) Social media friendly but most importantly it's very good. I've sampled burrito and taco dishes throughout my visits but my El Dorado #1 is definitely their "Signature Bowl" I rock it with: Carnitas, brown rice & black beans. They add guac, queso fresco, pico de gallo and mexican 3 cheese blend. It makes for a very good bowl.
Ambiance: Very classy high end decor that provides a great date vibe. Intimate leather booths, dark wood, red walls and contemporary lighting make for a very chic dining experience. The center bar has all the premium bottles and there's flat screens throughout the open dining area usually playing sport channels
El Dorado Cantina is open 24 hours and I've wandered in here really late/early morning and the food was still on point. The interior is pretty and so is the food presentation and the portions are fine. However, know that you are paying strip restaurant prices at El Dorado Cantina. Vegas is officially a foodie city and there are many Mexican restaurants that can offer what El Dorado offers but significantly cheaper. You won't get the ambiance or 24 hour convenience but that's what's out there. If you know this, then that won't stop you from visiting El Dorado especially at 3 AM in the morning because you know the premium you're paying. Enjoy...=)