Which is better: 5 sun gods or 1 temple of the sun god? I don't want to sacrifice all my sun gods if the temple doesn't do better!
Sun gods are more powerful not temple-ized. However, when you make a Temple of the Monkey God, all the other towers in its range are taken in and combined into the temple to make it have more power, plus now you have more space to build other towers, or more Temples if you like.
It is your choice, though, depending on your playing style.
If you fully upgrade the monkey temple, then it is leagues above the sungods. However, if you don't sacrifice to the temple, the sun god is better in every respect. To get a fully upgraded temple, if I remember right, you need 30k in each category: bombs(bomb and mortar), magic, ice, glue, and misc. Also, you can sacrifice a monkey village to the monkey temple to give it the buffs internally. This doesn't stack with any other village you might or might not have on the temple itself after you upgrade it.