The lack of TRIM will indeed make the G1 an interesting drive.
I expect it will settle at 40-50MiB/s.

I'm not sure about the Mtron, iirc it was generally pretty good at QD1.

@Christopher
What about the Vertex Plus?, the 120GB is cheap and the Indilinx was/is a pretty good sequential performer.
(not sure about the current firmware though)

or, you can pick up another Mushkin and put 10GB (or more) extra over-provisioning on it, it might do a lot of difference vs the standard one.
(it could be any drive of course but over-provisioning is interesting and none of the current drives are over-provisioned)

or, you can get one of the synchronous based drives and compare vs the async one I've got.

a lot of options, I'll be looking for another drive within a month or two, and there's always the new Intel