I happen to like the shadowrun approach as well. It is basically a variant of the GURPS approach with less impact and more predictable side effects. I would say that, the more you want to have magic be a significant force in your game, the less dramatic the side effects. Warhammer's (or, in a way, Call of Cthulhu's) effects of magic gone wrong are meant to show that only the idiots, the overly ambitious, and the insane play with magic.
I think the material power point was used in a way in an old FGU game called Swordbearer - I'd have to look it up to be sure but I seem to remember something like that. It's the "charm magic" kind of control, in which magic is less something people *do* than something people *point at other things* (or other people) -the magic is in the focus, the caster is just releasing it. You can even be more specific and state that you need a specific kind of focus to perform a specific kind of magic (a spell), resulting in casters being loaded down with charms, runestones, and other paraphernalia. Very visual, very conducive to natural and craft magic.
The lifetime pool I don't like at all, even if I think it was actually used in an earlier version of Warhammer FRP as well. It sounds too much like a delayed death sentence for mages, and they know it. But it makes a good background for a setting where mages are enslaved to provide their power to other people - mages are literally 'living batteries', except you don't recharge them, you discard them when they're burnt out. Very atmospheric, but not something I would like to play except for "uprising" campaigns where the goal is to fight against the tyranny of those who enslave the mages - but in that particular setting, I think it could be great. This is the kind of setting where magic is a curse for a person (because it means a short life of slavery), but it's a curse desperate people can use as a weapon.
The unlimited one I could use easily, because my games do not use the attrition factor much - I don't set up "dungeons" or similar where daily attrition is a factor, so the only limit for casters is how much power points they have - basically, they can spend it all in one encounter, because the pace of the game is such that, in all likelihood, the next one will be several days, or weeks, later. Which typically is what the NPCs are doing, if you think about it.
Of course, doing it by way of setting the pace of the game is a trick - once in a while, you *can* change the pace of the game and have them face two encounters in close succession. And see how they fare with depleted resources. But it's rare. Rare enough that they know it won't happen most of the time. Rare enough that thy can often prepare for it because it happens only in specific situations. But not never, which means it's always in the back of their mind.
One of the variants I tend to use nowadays is that a caster can reduce the power cost of a spell they cast by increasing the difficulty of the spell casting. Since I use a one-roll resolution (the casting roll integrates the resistance factor), increasing casting difficulty tends to reduce the statistical effectiveness of spells, so it's something you can do but you have to choose when to do (being a miser has it's drawbacks). Since I don't use mandatory prep time anymore, you can use prep time as a prop to reduce spellcasting difficulty.
What I don't do anymore: use power points as they are described in the original game, with a "standard tomb delver" pace (D&D dungeon delve kind of adventure). I don't do dungeon delve at all, I don't have fast-paced games, and I don't have a slow power regeneration rate.
