I recently went to Diego's while at a company conference, my team had a group dinner here. The menu was reasonable (for Vegas standards), the prices ($20-$40 per dish, pretty standard for Vegas).
We got a couple of the homemade (at your table) Guacamole, which was really good. They make it to your taste (hot, mild, normal). I ordered the Mole, which was quite honestly the best Mole I have had in a very long time. There were a variety of dishes at our table and everyone seemed to enjoy their dinner.
We ordered a variety of desserts, but NONE of them were that great. I ordered the Crepes, which sucked. Overall, It was good and I would recommend for anyone looking for good on the strip Mexican food.