We went to the first four or five, but tbh, it got a bit samey, the trouble with classic racing is that it's pretty much the same cars every time, not much evolution of course! The addition of Group C probably makes it more appealing to the modern LM go'er though.
Plus, for the older stuff it's more like 45 minute demonstration runs than actual racing, and with a big gap between each race it can get a bit boring especially if you are out at somewhere like Arnage or Mulsanne.
Now, if you are going to see a lot of classic (and special modern) cars parked up then it's a veritable feast!
BTW, I don't think Jenson Button has announced anything about going to the Classic, someone else did it for him, and I believe DailySportscar.com have removed the story from their website.