I don't know how it reacts on the vinyl in the long run (I've had no probs in the past) but I have used Mr Clean Magic Erasers before to get out deep dirt and stains and it has worked better in just a few seconds than most cleaners did after 20 mins of scrubbing...However I'm always afraid that if it works that well the chemicals can't be too good for the vinyl so I always immediately use a seat soap followed by a vinyl conditioner right after using one...just to be safe. Like I said, I've never had probs in the past with doing this and I've found the Magic Eraser to work better than anything else...plus they're cheap. Although if you use a daily seat cleaner you shouldn't ever really need it! Just my 2 cents worth...
PS...if anybody has had a bad experience or reaction on their vinyl from a Mr Clean Magic Eraser...please let me know so I know for sure not to use it any in the future!