Comparisons with other CAS

Macaulay Classic (D. Bayer, M. Stillman): +: very popular, many supporting scripts; -: speed, functionality (e.g., only homogeneous polys over finite fields)
Macaulay 2 (D. Grayson, M. Stillman): +: input similar to mathematical notation; -: speed, functionality (e.g., no primary decomposition)
CoCoA (L. Robbiano, University of Genua): +: Hilbert series; -: speed, functionality (e.g., no multivariate factorization, primdec, ...)
MAGMA (University of Sydney): +: functionality (number theory); -: not freely available
Gb/FGb (J.-C. Faugere, University of Paris 6): +: speed; -: functionality (only Groebner basis), not available at all (FGb)
Summary: Singular one of the fastest systems with largest functionality