I've had them on vehicles before and for my driving style, they were not that great. This is from at least 10 years ago, with a lower powered vehicle. Tires are typically the first and at times the only "mod" I do to my vehicles. I have not always done it right away but as soon as I can, I find something better. My disdain for these tires are based on personal experience. If they work for you, keep them. However, if you are a spirited driver, you will get annoyed fast and be looking for replacements.
I tried Pirelli's P7 AS plus on my Optima hybrid, when new they were some of the quietest, most comfortable tires I have used on a car. While tirerack.com's later review say their wet weather performance wasn't great, they were still tops of the big brands and I only noticed reduced performance after 30k+ of usage. The same can be said of their winter performance. For the first 2 years, they were like using dedicated winter tires. First AS tires I have used that behaved that way, of course their price increased after the reviews they got. For a "cheap" tire to replace the OEM Kumho TA31 (or maybe 71, can't recall), which would spin the tires when in Sport (271 torques off the line will do that) mode if you put your foot in it, I went with the General G-MAX AS-05. These are Ultra High Performance AS tires and they grip quite well in all conditions but their winter performance, while good, isn't better than the Pirelli P7 AS+. At around $100 each at launch, for 225/50 17 (upgrade over the 215/55 17), they were a good investment and perform quite well.
When you do go for replacements, if you keep the 18" size, upgrade them to 235/45 18 or 245/40 18, which would be better for this size and weight of the vehicle.