In reply to alanlgm:
I have always used Handbrake to rip my DVD's for use on my iMac, iPad, iPhone, Apple TV etc. I've not yet found anything better which is free. As you state some 'free' software watermarks the file & you can only get rid of it by buying the full software. Handbrake is free.
I'd stick with Handbrake & if you have a mac go on a few mac forums as there are some great tips which tell you how to get the most from Handbrake.
I've burnt over 500 DVDs via handbrake & never had any major issues.