I have only played a few Serhibas and not even for very long. BUT, I think somebody should stress here how inportant it is not to look at the Disciplines as spells in the same way you might look at D&D spells. This magic systme is much more based on the "Mage, the Ascension" paradigm of magic than the AD&D system. One of the great triumphs of the magic in this game is that it is more a question of what can imagine doing rather than what you are capable of doing. Naturally there are limits, within the ritual paradigm you cant do magic in combat and there aren't very many overt flashy results fom magic. BUT there are sorceries and summonings and endowments that are really open for great things that are immensely cool to be done.
Another important thing is the idea that the whole working of magic is a wholistic process involving set, setting and mood, delivery, conceptualization and dramatic impact. The best rituals I've seen worked have involved sometimes hours or days of preparation and complete lengthy descritptions of the kind that make people not used to scotts way of playing roll their eyes. It's definitely a fact that one ritual could suck up an entire hour of gameplay, and that's just the nature of the beast. But still when done right it is somethig to talk about for weeks afterward. And you always have to remember, is what I'm doing worthy of a movie scene, should this be a screenplay chapter? If it's not, you're not doing it right. You should come away from performing a ritual just WISHING you could see that happen on the big screen. Let me give some examples from film:

Sardo-Numspa's communion with hell in "The Golden Child"
The Green Fog scene from "City of Lost Children"
Frodo having a vision in Galadriel's water-thingy in "The Lord of the Rings"
There's more but I have to get back to work.