Romeo's soliloquy is much longer and involved than Juliet's brief verbal interlude. He says a great deal more about death whilst her reference is straightforward and simple.
On laying Parris' body in the tomb, and seeing what he believes to be Juliet's still livid corpse, Romeo says the following in lines 92 to 97:
Death, that hath suck'd the honey of thy breath,
Hath had no power yet upon thy beauty:
Thou art not conquer'd; beauty's ensign yet
Is crimson in thy lips and in thy cheeks,
And death's pale flag is not advanced there.
Death is personified in these lines and Romeo states that it has sucked in the sweetness of Juliet's breath, literally taking her breath away and thus causing her demise. He furthermore states that Death has had no power over his love's beauty for that has remained untarnished. Unconquerable Death has not conquered Juliet's loveliness for she has retained her pulchritude even in death. The red in her lips and her cheeks has remained and has not been stained by the paleness of death. Juliet is as beautiful in death as she had been in life.
The personification is extended in lines 103 to 105:
That unsubstantial death is amorous,
And that the lean abhorred monster keeps
Thee here in dark to be his paramour?
Romeo here compares Death to a tenuous lover, one who does not have the substance or body to share that love. He says that death is lean, further emphasising the lack of genuine love. Death is a despicable aberration that has imprisoned Juliet in this dark tomb to be his mistress.
When Juliet awakens and sees Romeo's corpse she says the following:
Poison, I see, hath been his timeless end:
Death is seen as a 'timeless end' - which means that it is everlasting and thus permanent. She wishes to get some of the poison from Romeo's lips so that she may also die. Joining her love in death would be an antidote to her intense grief.
For Juliet, death is her only option. Continuing to live when he is gone would be too painful a burden to bear. She therefore stabs herself with Romeo's dagger and dies.