This is quite a broad question, as Sir Philip Sidney wrote an entire sonnet cycle, Astrophel and Stella, as did Edmund Spenser, whose sonnet cycle was titled Amoretti. Here I will explore the basic overall differences in sentiment between the two.
We can begin by looking at "Amoretti I" by Spenser and "Not at the first sight . . ." by Sidney, respectively the first and second sonnets in each cycle. (Sidney's first sonnet is a take on the tradition of invoking the Muse before proceeding to write, and so we start with his second sonnet, which is where the collection begins in earnest.) The ending couplet of a sonnet is where the point of the poem is made, and so to discern the truest feelings of the speaker, we turn to the last lines. Though Sidney's sonnet is written in Petrarchan rather than Shakespearean form, and is thus arranged slightly differently, the same concept applies.
Spenser's ending couplet is as follows: "Leaves, lines, and rymes, seeke her to...
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