Positive response:
True... exactly...
I am all out for it.
I am in favour of it.
You have my whole/full support...
I am giving it my backing.
I can see no reason to oppose.
I urge you...
Please, do consider my words very carefully.
My reaction is extremely favourable.
Negatives:
I can't approve of it...
No, it bears no relation to...
I would find it difficult to (accept it)…
I'm not sure you are right about it...
Neutral:
My personal opinion is...
I'm inclined to think that...
It goes further than that...
That's one way of looking at it, but...
You would be well advised.