Truth is much of what Jeepatron mentioned. It does raise the center of gravity, but for many vehicles, that change is so minimal that the average user won't notice it. (This is why you see so many vehicles, that aren't necessarily designed for it, lifted) Now... if you're going 80+MPH, and decide to take a sharp turn.. well.. things might be a little different
One thing you MAY notice with a lift kit, on some vehicles (I don't believe the Renegade is included in this) however, is that your gas economy and handling change a bit... this is especially for vehicles that would normally ride lower to the ground. The change of wind drag and resistance when you change the gap under a vehicle that is designed around that gap being a specific distance, can be measurable. (It's also how some vehicles, especially at high speeds, can be drastically performance altered with a spoiler)
Overall, however, I'd mainly be worried about the materials the lift kit were made from... I've seen a few lift kit springs break when their tension changes a bit, and almost universally, you find porous gaps in the broken metal parts. (QA issues) THAT, is the only concern I'd have, when buying a lift kit from a 'no name' brand. (aside from fitment, obviously)