I had a GREAT stay here last week. Upgraded to a huge, 2-room suite (xx07) at check-in. While the suite did not have a view of the Petronas towers, it was definitely a great room with plenty of floor-to-ceiling windows overlooking the Pavillion shopping mall as well as the local streets behind the Westin.
The room also overlooked the Marriott and the Ritz Carlton, both of which are right next door to the Westin.

The highlight of our stay was the breakfast in the Living Room. This must have been the most elaborate breakfast buffet I have ever seen.

Plenty of made-to-order warm food stations (one station for breakfast meats, including steak. Another station for Indian Rotti/curries, etc)

Just when we thought we had checked out the entire buffet area (it is spread out across the entire dining room - not just confined to one area), we discovered the Bakery.

This place looked like a high-end bakery with dozens of prepared items (quiches, breads, baked sweets, etc). All were included in the 68-ringgit buffet price (which was waived for Plats).
Just as I walked to grab the last croissant sitting on the counter, the oven beeped, and the door swung open revealing a new batch of fresh, warm croissants. Yummy!

The lounge was also quite nice, though the food options there are a bit disappointing.

All in all, it was a great stay. We had a late flight (midnight) out of KLIA, and the front desk granted us a very late checkout (6PM).