Plato and Ficino - agreement
Plato's Symposium and Ficino's Commentary agree in 'the vision of spiritual love as an ennobling force, in contrast
to carnal love, which debases, a vision which in Socrates' speech pro-
duces the famous description of a ladder of love leading up to the
pure idea of the good and the beautiful.' (Alan S. Trueblood, 'Plato's Symposium and Ficino's Commentary in Lope de Vega's Dorotea', Modern Language Notes, Vol. 73, No. 7 (Nov., 1958), pp. 506-514 : 507.)
Plato and Ficino - divergence
Ficino Christianises Plato : the spiritual love of which Plato talks in the Symposium is transformed, Christianised, by Ficino who 'broaden[s] it into a conception of love as the motive power of the universe.' (Trueblood, ibid.)
In more detail :
In the Symposium of Plato Ficino found the
completion of the arc from God to man; for him the discussion of the
meaning of personal love in the Symposium completed the pattern. Just
as courtly love fitted into place at the end of the scale of Christianity, so
the Symposium fitted into place at the end of the scale of Platonism; the
pattern was complete, the two scales were really one, reaching from God
to man and from man to God. All the physical drives of human love
might be justified spiritually and at the same time idealized intellectually,
because love in man is not only a God-given and cosmically necessary
and irresistible search upwards toward a perfection which is both spiritual and intellectual; it is also an irresistible, God-given, and cosmically
necessary compulsion downward to create the likeness of Divine Beauty
in the physical world. Platonism and Christianity, seen as love, are one;
and the term "Platonic love," which Ficino invented, embraces love in its
widest sense. Love for Ficino is the dart in the eye and the fire in the
heart of the courtly lover, becoming idealized through the process described in the Symposium and ultimately revealing itself as identical
with the world force of Neoplatonic Christianity. All the known love traditions are fused to show how love between individual persons derives
from the love between the individual and God. (Sears Jayne, 'Ficino and the Platonism of the English Renaissance', Comparative Literature, Vol. 4, No. 3 (Summer, 1952), pp. 214-238 : 227-8.)
This interprets Plato's ideas and arguments in the Symposium beyond anything Plato himself would have recognised.
Plato and Ficino - incompleteness
Jayne points out that Ficino's actual commentary is limited to only six
specific passages of Plato's dialogue; its main thrust consists rather in the
exposition of Ficino's ideas about love. Ficino's awareness of the dual nature
of his treatise is reflected in a disparity of titles: he called his 1474 Tuscan
version of the work Sopra lo amore and often called his original Latin treatise
simply De amore with no reference to "Commentary." (John C. Nelson, 'Commentary on Plato's Symposium on Love by Marsilio Ficino and
Sears Jayne', Italica, Vol. 65, No. 2 (Summer, 1988), pp. 164-165 : 164.)
Ficino - a good read ?
Make up your own mind from the online text : https://www.scribd.com/doc/149506301/Marsilio-Ficino-s-Commentary-on-Plato-s-Symposium-Sears-Reynolds-Jayne-A-M
Page through the Introduction and the Latin text to find the English version.