I have some Alumitones and like them, but they're not for everyone.
They have that super clean/hi-fi thing - the spectrum is broad and flat.
What I like about them is that they make for a clean and broad palette if you like to use eqs to build tones.
They interact with amps differently than other pickups - the 'fat' and 'bright' pull-pots on my amp don't respond to them at all, whereas with traditional pickups, it's night and day. They certainly make the most of my amp's para-eq, though.
Otherwise, they can handle a ton of distortion and stay tight (great for djent), and because the signal is so quiet and powerful, they can withstand a lot of processing without adding noise or the tone degrading.
But as one board member put it - they're just not for "grunt'n'squeal" rock'n'roll!