While I've had good luck with the Pioneer speakers in the past, I'd go for the Kenwoods. By "good luck" I mean they've never blown on me. However, the Pioneer speakers seem to over-rate their bass a bit. Their treble is good, but the bass was a bit weak. Give the Kenwoods a try.
I only have one concern about the Kenwoods, though. There's a story being circulated that Kenwood is about to pull out of the audio industry. I've seen this mentioned a few times over at some of th home theater sites. At this point, it looks like a rumor, but you should still be aware of it in the event you do go with their speakers.