Outdoor use
Ferrite magnets are very chemical and rust resistant, while neodymium magnets are not suitable for outdoor use.
Brittleness
Ferrite magnets can break into pieces when you repeatedly put a strain on them. Neodymium magnets are very brittle and crack easily, which can lead to injuries of user or bystanders.
Loss of adhesive force
Neither ferrite nor neodymium magnets lose their magnetisation by itself. They can only be demagnetised by external factors like heat or strong external magnetic fields.
Standard tolerances
Neodymium magnets generally have a tolerance of +/- 0,1 mm.
It's more complicated with ferrite magnets: Their height-related standard tolerance is +/- 0,1 mm; their width- and length-related tolerance is 2%, but at least 0,1 mm.

Machining and tolerances
Ceramic magnets are very hard and brittle, consequently machining must be done with a diamond wheel, and is easier when done prior to magnetization. Standard tolerances for ceramic magnet dimensions are +/-.005" for ground dimensions and +/- 2% of feature size for as sintered dimensions. Because of their brittleness these magnets will not withstand impact or flexing. We recommend that they not be used for structural purposes. Ceramic magnets are chemically inert non-conductors, which is a benefit in many applications. However, this feature does eliminate the use of the EDM process to produce samples or special shapes.
Temperature constraints and methods of magnetization
Maximum operating temperature for a ceramic magnet is 250°C. Although you will experience magnetic losses when operating at elevated temperatures, the losses are recovered when the material is brought down to normal ambient temperature. However, operating in very cold temperatures (-20°C) can result in permanent losses of magnetic strength unless the circuit has been designed for such extremes.
Magnetization: ceramic magnets must be magnetized in the direction of orientation, which is the same as the direction of pressing.

ceramic magnets Applications:
Hard ferrite magnets have a wide variety of applications: Speaker Magnets, DC Motors, Sweepers, Magnetic Separators for ferrous materials, Automotive Sensors, MRI’s, Reed Switching, Hall Effect Devices, in Assemblies such as (separating, holding, lifting, retrieving, and latching), Refrigerator Magnets and Arts and Crafts as well as many other novelty applications.

Materials
Soft ferrite is generally composed of two formulations, manganese and zinc (MnZn) or nickel and zinc (NiZn). The MnZn are generally used at frequencies below 3 MHz and exhibit a higher permeability (µ’) and saturation induction levels (Bsat).  NiZn ferrites have a very high resistivity, are most suitable for frequencies over 1 MHz and high temperature applications.

Ferrites:
High permeability pressed parts (10,000 – 15,000 ui)
Impeder rods (high ui) (welding applications)
Pot cores (for proximity switches)
Bobbins
Tile for anechoic chambers and other absorbing applications
Magnets:
Oriented Ceramic
Neodymium
Alnico
Samarium Cobalt
Plastic/Rubber Ferrite