There is no single, monolithic Jewish opinion. Many Jews are unclear on exactly what the Christian idea of God is and what is worshiped in Christianity. I learned to separate the construct into 2 parts, the character and the idea and in muly understanding, Judaism and Christianity share a God character but not a God idea (whereas Judaism and Islam share an idea but not a character).
It depends which Jew you ask. Generally speaking, Jews accept that Christians, Jews, and Muslims all worship th God of Abraham. But the Christian thing is tricky, because mainstream Chrstianity teaches that Jesus is God (Trinitarianims), and this idea flies in the face of Jewish understanding that a man cannot be God. So you also have some Jews who say that Christian worship of Jesus is avodah zarah (literally "strange worship," meaning idolatry).