We get this question a lot because a lot of people associate AlNiCo and ceramic with particular tone qualities.  But these qualities are only true in very simple and similar pickups. 

We make pickups based on the desired tone, so to me, the type of magnet is not a feature.  It is just a tool we use to get the tone we are after.  We use ceramic almost exclusively - here's why.  AlNiCo carries a fairly weak field and is inherently unstable.  Its magnetism will change over time due to changes in temperature, physical shock, and proximity to permeable materials.  Ceramic magnets are very stable.  Now, if you make a simple pickup and just swap AlNiCo for ceramic magnets, it will sound brittle.  That is because the magnetic field is very strong within the ceramic magnet.  Many have tried this approach with poor results. 

Our pickups are designed with consideration for how we want to project the magnetic field onto the strings and how and where the changing magnetic field is going to couple to the coil.  We design a magnetic circuit using materials chosen for their magnetic permeability - steel, brass, copper, tin, etc. – to produce pickups using ceramic magnets that are not at all brittle.  In fact because we really understand how to control the magnetic field, we can create a pickup that is very dark - like a badly aged AlNiCo.  AlNiCo is generally used in very traditional, simple pickups, where there is not a lot of flexibility in how the field is controlled.  As our pickups are cast in epoxy, we can make very complex structures to control the field to get the tone we are looking for.