How does it compares to IK Leslie ?
I think it is the same as used in the B-5 from Acoustic Samples.
And I think CPU is not that much high.
The B-5 Leslie stacks up very well against the IK Leslie, with lower CPU demand. I downloaded IK Hammond B-3 trial version in June when it was on sale, and compared it to B-5 v2 and Blue3. B-5 is still my favorite overall.