I think the first couple of years she filmed Cathe Live the pace was a bit slower and she took more water breaks. So if you want slower paced I would try one of the first 100 workouts. She really hit her groove and is super comfortable with the process so her personality really shines through now.
I love it! It's just like taking a class with her at her gym!
The last year and a half they seem to be faster paced with fewer water breaks. I don't stress about it if I miss the first rep or two of a set, I can usually add it on real quick before she changes exercises. You can also pause for a minute to get water too.
ETA: To answer your question, I think the intensity is about the same. Her newer dvds were specifically geared toward intermediate level so they are less intense than Cathe Live. You will also find some "easier" Cathe Lives that aren't as long or as intense as her dvd workouts. I love the variety, there is always something that I can choose to fit my energy level or training plan.