Yeah I've tried ab hits--I think I still have it gathering dust somewhere LOL. Thing is, I've been training abs w/heavy weights at the gym for about 10 years now. So doing any kind of core work without weights just isn't challenging. I used to do the weighted ab workout twice a week, now I've switched to once a week & I reserve one day for core work only, be it pilates, Core Max or whatever.
But the only two core workouts that really "do it" for me are Core Max & the MTV Pilates Mix. Everything else has been totally disappointing. I still try to vary the 15 or so pilates DVDs I have, but I feel like I'm wasting my time & money.