I had been intrigued by P90X for a while. I had the opportunity to purchase 6 of the DVD's (all the strength ones, which all include Ab Ripper X at the end so it's like I got 7 of the workouts) from a swap site. I'm in the first week of the Classic rotation. Here are my thoughts to some of your questions.
1. The weight work is a tough as you want it to be. You are encouraged to lift as heavy as you can and to set for yourself a rep total using that weight. If you go really heavy, you might only get out 8 reps before failure. If you lift a little lighter, you'll get out 12-15 reps. What I also really like about the weight work is that you aren't doing the same body part for more than two exercises in a row. By constantly mixing up which muscles are used, I found I can stay with my heavy weights for longer and really fatigue the muscle. I have some major DOMS this week, and it's felt good!
2. Tony has a pretty goofy persona in these workouts. Some people find this fun and engaging, some people find it annoying. I'm personally not bugged by it. I can only speak for the strength DVD's, but I'm working so hard that most of the time I'm not noticing what Tony and crew are doing. I had heard a lot of mixed opinions on the cardio workouts so I opted not to buy those. Instead, I'm doing Cathe, Christi, CIA, or whatever I enjoy for cardio. This is keeping the fun factor there for me. If I had to do the same 12 DVD's for 3 months, I might go insane. Knowing I can pick and choose what cardio I want to do will keep me sane!
3. Even though P90X only has one leg workout, I have read on other forums that if you buy the full set that PlyoX is such that it really works the leg, so it's like having a second leg workout. Since I don't have PlyoX, I'm counting my step workouts (in place of PlyoX) as a 'second' leg workout. I'm not sure that I'll be able to do Legs and Back the whole time and may substitute some Cathe lower body workouts later in the rotation.
4. I'm also not sure if I can do Ab Ripper X 3 times a week for the whole rotation so I may substitute Core Max segments or a couple of segments from Ab Hits in a couple of weeks. But Ab Ripper X is an effective workout, so I'll try to do it 2 times per week, and substitute the 3rd time.
5. Yes, P90X is pull up intensive. I'm using the heavy band anchored from a high point option. What's nice about the back exercises is that Tony has crew members demonstrating how to do the exercise with the band, and how to use props like chairs to do the pull ups while you're building up to unassisted, full pull ups. I would be TOTAllY surprised if you didn't meet and exceed your expectations for pull up development using P90X.
IMO, if you really lift as heavy as you can, clean up any eating infractions, and work in quality cardio, you'll definitely see the benefits you're looking for from this series!
Good Luck!
