In order to answer whether or not these sonnets are effective love poems depends on the definition is. Look at your assignment to see how your teacher wants you to define an effective love poem and then compare that definition to the poems. You may want to consult your class notes to see if your teacher discussed examples of an effective love poem. The reason I suggest this is because love is subjective; and, to get a good grade you need to answer according to the assignmentn requirements.
However, as far as Shakespeare's sonnets are concerned, he generally posed a problem within the first three quatrains and came to a resolution in the ending couplet. It seems that Shakespeare follows suit with both sonnets. But these poems are not written from a romantic perspective, per se; they are more realistic and more mature than a youthful, puppy-love-type poem that focuses on the beauties and excitement of love. Rather, these two sonnets on the realities of everyday love that endures throughout the years.
Sonnet 27 seems to show either obsessive love or long-lasting love depending on how you look at it. He dreams about her at night and has a tough job during the day. Isn't this just life?
Sonnet 130 focuses on physical characteristics that are not generally associated with love, but in the end he shows that he accepts her for who she is; and that seems like real love.
So, find out the definition that your teacher wants you to analyze and then compare the sonnets to that definition.