It's hard to make a strong argument for the SRX if fuel economy is one of your priorities.
EPA ratings for the 2013 Cadillac SRX land at 16 to 17 mpg in the city and 23 or 24 mpg on the highway. And considering that a number of larger crossovers--like GM's own full-size SUVs such as the Buick Enclave, or even the Cadillac Escalade Hybrid--get around the same, with much more passenger space, or towing ability, it's impossible to call the SRX fuel-efficient.
GM didn't improve things by swapping the 3.6-liter engine into the SRX. Ratings actually went down 1 mpg versus the previous 3.0-liter engine. We saw a real-world 19 mpg in an extended drive of a 2012 SRX.