Love more than one
Love only one
Both have their own pros. Monogamy is somewhat protected, your heart is no longer out there to be broken. There is a safety in the minimalism that can be monogamy (I say can be, because most of us know all to well that monogamy usually happens back to back). Poly leaves you open to being vulnerable. In that vulnerability to can find strength. But it does leave you open to hurt. Poly also allows you to love more than one. There is a power in being able to give that to people honestly. I get great joy from loving .. my lovers.. and in turn being loved...
You are on a poly board asking poly people pro and cons. Its been so long since I have been monogamous, the only benefit I can see is protection. So I know for me, I cant answer this question very honestly.