I disagree about Sasha and Kristi being less impressive in person, but that's just my opinion.
For Sasha, I first saw her live in 2002 (at the Nationals short program). I was sitting way up in the nosebleed seats, which in Staples Center is WAY up there. She was the only lady who I could feel the expression from way up in my seat. I was a casual fan of hers before, but this made me an uber fan. I feel her spirals are more impressive in person as well.
For Kristi, I've seen her twelve times in person and she's never disappointed. When I saw her do Bridge Over Troubled Water in person perfectly it brought tears to my eyes (which rarely happens for me). Yes, I'm the hugest Kristi fan in the world and may be biased, but through my eyes while watching her skate live she's always been great.
In general for live vs. TV....spins always look faster in person, pairs lifts can be less impressive in person if you're sitting high up, or more impressive if you've got a great seat. TV can't capture the ice coverage that well, but you always get a close-up shot (well, most of the time) while live, no matter where you sit the skater will be away from you much of the time. A jump close to you will be more impressive than one done on the far side of the rink. As has been pointed out, facial expressions are hard to see live, unless you've got a front row seat.
For the most part, I enjoy everyone I see live (even those who aren't my favorite.) And live competitions have an extra "oomph". One time when I was fortunate enough to get really great SOI seats, Todd Eldredge did his triple axel right in front of us and ice flew off his blade right past us...that was thrillilng! Now that's something you can't get through the TV.
