The Short Story - Mexican Food For Americans - edible, but not that much up from Taco Johns.
Located in both Eau Claire and in Chippewa Falls, Cancun is a decent American Mexican restaurant. Nothing too special, nothing too spicy, with generic sauces. The staff is attentive, food served fast (straight from the heating table, into a tortilla, onto to your plate), it is a good place for a business lunch - in and out in 30 minutes, but it doesn't feel like they are pushing you out the door (even though they are in working hard to flip tables).
The ubiquitous chips come with a decent, although mild (err, american style) salsa and this odd ranch dip, that has this gluey nasty consistency and odd taste (although surprising ok on top of the generic burrito you ordered)
Ok if you need a decent looking place (think a smaller chi chi's) with generic american mexican food (think chi chi's)
If you want real mexican food - go to where the staff at cancun eats - Tacqueria Sandoval, 2824 London Rd. - Now that is great mexican food -- real mexican food.