It is an abstract ideal - driven by emotions rather than nature.
Yes Daniel, that is a reminder of something important -- that ideas/abstractions generate emotions every much as strong (or more) than physical feelings. So it is not enough to say that something "is an abstraction so therefore it isn't real" -- Abstractions may not have physical reality independent from us, but they can certainly generate strong feelings nevertheless.
There is much they have in common - we have just been discussing what major differences they have. I think there is far more common than not.
I have long been an admirer of some of the work of John Stuart Mill -- I am less familiar with Bentham. But certainly in general to the extent they are both aimed after "happiness" they have much in common. The old saying "the devil is in the details" applies.
In my mind, the ideas fit together perfectly. If one places "greats happiness for the greatest number" at the center
Yes, that IF in that statement is the big hurdle.... and that IF is really at the center of much of the rest of the issue. Who has the "right" to enforce their view of the greatest happiness of the greatest number on everyone else who disagrees?