I have the Hero3+ and think it's fantastic. If money is not an object, it is worth it and is really fun for the whole family. You wind up seeing and remembering your trips in a totally new way.

As far as a pair of 64GB cards, I think that's a bit extreme. One 64GB card will hold a few hours of 1080 video at the highest frame rate. I like the Hero3+ because it has built in WiFi and a remote - so you can turn it on and off as needed. Going through hours of video from a vaction can be daunting - at least with the WiFi, it gives you flexibility to record only when you want to. GoPro also offers a free smartphone app which is easy to use as well.

And the picture quality is excellent. It can literally be an all-around camera on a vacation. I would recommend you purchase the LCD back if you want to use it as a camera for stills though.

I would recommend an extra battery or two if you are going to be out all day. They only last about 2 hours of constant use - so if you are out all day, you will want a backup and relatively speaking, they are not that expensive. Get them on Amazon.

I've spent $150 in accessories so far. It's a bit of an addiction, but we are having a LOT of fun with it.

Good luck