Hey,
I too, had this decision recently. I actually selected the Riu Vallarta, which is the sister property to the Riu Jalisco. I also read the trip advisor reviews before booking, which was a bit daunting. But in the end I decided the Riu Vallarta was my best bet because of the value, the reputation and the location. It seemed to me that travel agents, in particular, love the Riu properties, so I figure that has to count for something. They are not going to send you somewhere awful where you and your guests are going to be miserable.
If there is a theft at the property right now, I would expect the person would be caught and fired or otherwise moved on by the time you get there! Its just bad for business so the Riu people aren't going to take it lightly.
I'd recommend reading the thread about the Riu properties in this forum, it is super helpful and the reviews are generally positive.
Good luck with your choice!