Denver will offer more in the way of open time for aggressive bidding. Las Vegas seems to be going fairly junior. I'm not sure what the time to hold a line is in either base but given that Vegas is still growing it may be faster there. Keep in mind that with Vegas, if you can't hold day turns you're almost assured to see a minimum of 1 redeye per trip, maybe more. Depending on the SLC commute, trips are commutable at both ends if you can find a flight home after about 10pm LAS local time.