Carlsbad is a beautiful area, and the Westin is a superb hotel. We rented a car, and the valet service was convenient. The hotel staff was friendly. The Ocean Pearl Spa is delightful and has an excellent couples massage - expensive but relaxing.
A few things that I thought could have been better.
We booked our trip through Expedia and booked a Premium Room, 1 King Bed, Balcony and View. After getting to our room from a long flight we found the room had 2 queen beds instead. I went back to the front desk and asked if I received the correct room, they said the other 1 King rooms were taken so we were "upgraded" to the two queen beds. I booked this room 2 months and didn't feel the 2 queens were an upgrade. We kept the room and didn't question any further. It would have been appreciated if the person at the front desk explained this before getting to our room and making sure it would not be an inconvenience.
The second experience that could have been better is the location of our room. To access our upgraded room, we walked through the lobby, outside along the pool to another building, take an elevator up one story, walk through that building, outside to another breezeway, into another building, take the elevator up two stories, and at the end of that building was our room.