Why the difference between the two do you think?
The biggest - price. When Monde first launched it was around $700 PSF. That's way too high for such barren (though when it's built up it'll be great) area. River City (different location but same idea - nothing at the time around it) was also better in that the developers recognized you've got to price accordingly to entice people to take a chance on an up and coming area.
Second thing is Tridel seems to really have a knack for getting people to buy their condos precon. Look at 10 York - 80% sold in about 10 days in late 2012. That's usually a dead time in the market, and at the end of last year doom and gloom about the condo mark was at a high point. Kudos to them.
I think it also goes to show that the general public just doesn't care about architecture like most on UT do. Monde is a Mosh Safdie design, and Aqualina doesn't look like anything special. GG hyped up the Safdie design, and it looks great, but if that means higher pricing then people won't put the money up - most of the time.
One exception: Mirvish-Gehry. The crazy design + name will make people go a little ga ga in my opinion, but you also have to consider the location: King and John. Also the towers just look so damn cool and are collectively a huge mega project, which if you notice sell incredibly well (see: Maple Leaf Square, Ice, Burano/Murano, Aura, 1 Bloor, RoCP, the Casa trilogy, etc)