You have to balance substrate thickness with thermostat set temperature. You will need to bump up your thermostat a few degrees. Basically try to keep the floor of the cage 95 or below, while making the top of the substrate 90. I have found that substrate layers need to stay under 1/2" thick for this to work.
Pros:
+ looks
+ easier to spot clean
+ absorbent
+ odor absorption/masking properties
Cons:
- cost
- harder to do a complete cage cleaning
- can make a mess everywhere
- harder to maintain proper temps