I don't have any real hands-on advice to offer on the game itself but I will say not to buy it for 20% off. You can have myself or someone else who owns Cities XL buy it and gift it to you for 50% off instead ($19.99) and send them Paypal gift to cover it. 50% is my usual minimum discount for pre-ordering a title I know I'll play immediately on launch.
Cities XL Platinum has only been bundles once that I know of (Humble Focus Bundle) but does show up for 75% off in the bundle stores as a separate title fairly often. But it's also a 2012 game.
The original Cities XL line was criticized for being a bit buggy and some poor design decisions. XXL supposedly runs on a whole new engine and maybe they fixed that stuff. I'd wait until the 4th and see if there's any pre-release reviews before buying. Pre-order discounts run until the 5th.
Reading around a bit, one of the biggest complaints about XL is that it's more "city builder" than "city sim". You plant the buildings you want and the city works with them but you don't have the same economy or neighborhoods going derelict or traffic flow or residential neighborhoods being too far from commercial districts aspects that you have from SimCity. If you're interested in a casual builder game, XXL might work (assuming they haven't changed from XL) but if you're more into the simulation aspect, maybe wait for Cities Skylines
by Paradox due out in the next few months. Paradox is all about simulation games so you'll almost certainly get a solid title from the nuts and bolts mechanics aspect. Judging from the screenshots, XXL looks a little prettier but Paradox knows simulations (almost to an off-putting extent when you're told to watch five hours of YouTube tutorials before playing Crusader Kings II). All in what level you're looking for from the game. Edited, Feb 1st 2015 6:46pm by Jophiel