We present the detailed analysis of the spherical s + p spin glass model with two competing interactions: among p spins and among s spins. The most interesting case is the 2 + p model with p ≥ 4 for which a very rich phase diagram occurs, including, next to the paramagnetic and the glassy phase represented by the one step replica symmetry breaking ansatz typical of the spherical p-spin model, other two amorphous phases. Transitions between two contiguous phases can also be of different kind. The model can thus serve as mean-field representation of amorphous-amorphous transitions (or transitions between undercooled liquids of different structure). The model is analytically solvable everywhere in the phase space, even in the limit where the infinite replica symmetry breaking ansatz is required to yield a thermodynamically stable phase.PACS numbers: 75.10. Nr, 11.30.Pb, 05.50.+q Spin glasses have become in the last thirty years the source of ideas and techniques now representing a valuable theoretical background for "complex systems", with applications not only to the physics of amorphous materials, but also to optimization and assignment problems in computer science, to biology, ethology, economy and finance. These systems are characterized by a strong dependence from the details, such that their behavior cannot be rebuilt starting from the analysis of a 'cell' constituent but an approach involving the collective behavior of the whole system becomes necessary. One of the feature usually expressed is the existence of a large number of stable and metastable states, or, in other words, a large choice in the possible realizations of the system and a rather difficult (and therefore slow) evolution through many, details-dependent, intermediate steps, hunting its equilibrium state or optimal solution.Mean-field models have largely helped in comprehending many of the mechanisms yielding such complicated structure and also have produced new theories (or combined among each other old concepts pertaining to other fields) such as, e.g., the spontaneous breaking of the replica symmetry and the ultrametric structure of states.Among mean-field models spherical models are analytically solvable even in the most complicated cases. Up to now only spherical models with one step Replica Symmetry Breaking (1RSB) phases were studied, mainly due to their relevance for the fragile glass transition.