Locking the mirror up is really only "necessary" if you're shooting with a long lens (100mm and up if I had to guess), or if you're using a crappy tripod. If you've got a wide angle lens on your camera and you're using a good tripod, you'll likely never see the difference. Oh, and you won't have to worry about remembering to turn mirror lock up off when you're done.
I like picture number 2 best. I might have liked 3 better, but I'm not digging the green light that's shining all over everything. It isn't as evident in 2.