Sales at Uptown have been fairly slow as far as I've heard. The price points were not appropriate for the standards of interior finishes that were being offered and the target market is sophisticated enough to know there are better deals to be had elsewhere.
There was a change in gears several months ago and the marketing campaign changed - that suggests that a different approach was needed to boost sales. It is my understanding that traffic to the sales centre has been slow pretty much since the project opened and I've also heard the placing the sales centre on Yonge St. may have been a strategic mistake.
Now with the two towers in direct competition, Crystal Blu appears to have better value, so that certainly isn't helping Uptown. I wouldn't be suprised if Crystal Blu broke ground first or if Uptown underwent a substantial revision or is cancelled altogether and the site sold to another developer.
Also Uptown has substantially more units to sell then Crystal Blu, so obviously it is going to take longer, but Crystal Blu really did have a very strong start (I've heard as much as 40% sold... but either that is an exagerated figure or there is a strong investor component to those sales).