The Forum is my favorite place to shop on the Strip. There are a lot of high end stores such as Hermes, Cartier, etc., but there are also the lower end places that are 100x more affordable (quite literally) such as Nike, Victoria's Secret, and Banana Republic. There are constantly sales and I always leave with something in hand. My most recent visit was on Christmas Day (all stores were open!) and I was able to nab a few things for myself. One of my favorite stores is Longchamp - they have so many colors and styles here - they even have a sale section - woohoo! I don't think there are any other Longchamp stores in Vegas, so big plus for that!
The down side to coming here is that it is PACKED (granted I did go on Christmas day) but when I've gone here on other occasions, it's pretty crowded. It gets really hot and stuffy in there due to all of the congestion. Also, I found it hard to navigate since there are not clear exits. I found myself circling the shops a few times before I could make my way out. But it's all good - I typically come here after eating at Bacchanal, so I better walk around a bit to burn those calories!