Definitely too low, I get GeekBench of 6000 with i3-2105 3.1Ghz under 10.7.3.
My other system w/i7 initially got performance halved with 10.7.4, but it went from 5400 to 12000 after adding SSDT using MB as described above.
So my question: Your low GeekBench score under Lion, was it with 10.7.4 and SSDT installed?
If not you may have had the issue where 10.7.4 is messing up with the Intel power/performance management, where processor keeps running at a low frequency (fixed w/SSDT), and still have the same issue with ML.
As far as ML performance, I am trying to install ML on both of my system, unsuccessfully