While I am a fan of the Aladdin and that is where I usually stay when in Vegas.....if I did not care about earning points (Aladdin is a part of SPG) and price was the same I would choose MGM. MGM is a great hotel and never really had a bad room there. Aladdin is not a bad hotel but MGM just has a better product.

Now, as others mentioned the dates of your trip can make a big difference as to rates and it can be hotel specific because one hotel may have a huge function that fills it up where as other hotels are relatively slow. There should be A LOT of hotels in the $100 range in a "normal" Sunday-Thursday time frame.