If you approach it as a completely different game than it's not awful, it's not a great as SC4 but it's a completely different type of city building game.
If you are prone to comparing other CB games with SC4 and do it in CXL, then you'll be sorely disappointed in what you get.
Cities are very static in CXL, they don't grow like they do in SC4 and that to me is one of it's most basic pitfalls in CXL and that which makes it boring to me.
Sure, you can build really pretty cities in CXL (although you can do so in SC4 too as I've seen in many city journals), however for me the fun pretty much stops there. Personally, I would have been overjoyed with CXL if they had simply made it so that the city evolves over time, plop and play games to me are rather boring, like the bastard child SimCity Societies.
If you can buy it for $9.99 or $14.99 then maybe it would be worthwhile, but not at $40 Not to me anyway.