I use velocity when building something and fire/blob/fancy to view it, because it looks pretty I only use pressure or heat to fix some problems involving those two. Persistent is completely useless to me, but oh well...
I used to use fancy. but I realized fire is fancier :P You guys gotta fix the glowing metals on fancy view. Anyways, I like fancy stuff. Tough I choose usually what I'm working. If I'm working on a heater, I pick heat view. If it's some kind of pressure thing velocity fits(It's easy to understand for me). When I'm working on a nuke, I view both.