Well, in a nutshell, they're great quality, lots of choices, great hardware, and easy to install.
Hardware - their hardware is made by Blum, which is known for quality. They have soft close drawers and doors at very reasonable prices. Their drawers are huge and hold tons of weight (all our dishes and bowls are in one drawer, for example)
Choices - I think they have 15+ different styles you can choose from, or mix and match. Also, if you want to change them out in 10 years, you'll probably just be able to buy new doors/cover panels
Install - instead of being a fixed kickplate, they're on adjustable legs that you clip the kickplate too. This means that levelling them is much easier. No shims required. Additionally, the uppers are hung on a rail. This means that you don't have to worry if your cabinet doesn't hit a stud. You level the rail, screw it into the studs, and then hang the cabinets. All this makes it much easier for a DIY'er to do it.
Oh, and cost. They're pretty reasonable, though I haven't done one in a while, so I can't speak directly to it. If you're really interested in it, go over to ikeafans.com. It's a board much like this one that focuses primarily on IKEA kitchens. They can answer all you questions, and answered lots of mine!