I've been investigating mouse sensitivity feedback, and I'd like to share what I've uncovered so far:
Due to this thread, I've tested a LARGE variety of mice, including but not limited to
G9 (Both is OS and SetPoint driver utilization)
G9x (Both is OS and SetPoint driver utilization)
G400
Razer Naga
Razer DeathAdder 1800
Steel Series Sensei
CM Storm Spawn
Saitek RAT 7
A non-Logitech OEM mouse that came bundled with a PC
On BF 3 with the latest patch, online, on a server with sub 60ms ping times, with each mouse set to 800 DPI (if possible: the DeathAdder could only do 900) and 1000 reports per second (if possible), every mouse had a similar real speed to in game speed performance. That is, moving each mouse roughly 1 inch on the mousepad resulted in basically the same movement in game. Where the mice differed (in terms of tracking) were accuracy, stability, and each mouse's own slightly different acceleration curve, but the speed overall remailed the same.
I tested with sensitivity set at both the 50% mark and at my preferred sub-20% mark. On all mice, I had the same difficulty playing at 50% and same comfort at sub-20%. Also, fine aiming was difficult for me at 50%, but I got very smooth performance at sub-20%.
Mice were tested in groups of 3, with the G9x being used as a reference mouse, on the same extra-large mousepad. I also FRAPSed some play to review after playing to check on my accuracy. There were some slight over and undershoots when I switched between different mice with different sensors, but these were minor enough that I chalked it up to shape and minor behavior differences.
The best conclusion I have is this: At this point, certain people may have to reduce the sensitivity of the in-game Battlefield 3 levels (try messing with both sensitivity bars), and on my system (My work test system is a G73jw-A1), mouse brands do not drastically affect mouse speed when set to the same DPIs. Personally, I have it set to what looks to be between 10-20%. Also, if you have the mouse running at 800 DPI or higher, try playing with the Raw Mouse Input setting.
On the SP 6.30 vs SP 6.32 discussion: I've talked with the software engineers and QA team. The only change happened was to how the driver handles USB enumeration timing to make it play nice with Windows 8. Tracking should not have been touched or affected. To test, and when possible, I will attempt to set up two PCs side by side, each running a different SP and on the same server, and see if there is a noticable difference. I'll have someone else install the software on computers without telling me which is which, and give it a test. (Personally, though, I'm not having a problem with 6.32: I pulled a 27-7 match last night with over 5K points, over 7.5K with ribbons, as Assault without using a noobtube or shotgun)
Now I'm going to have to restore my system as one of those 3rd party mouse software packages killed the ability of my mouse to scroll in browsers.
I'm in the same situation, and it's intollerable.
I've ALL Logitech products, Headset G35, Mouse G500, webcam Quickcam IM/Connect and even keyboard from Logitech.
I've bought my G500 mouse last year to play Battlefield BC2 and all was fine.
Instead, from when Battlefield 3 was released, I suffer of this problem you say.
Now I'm wondering about buying a Razer Imperator because I'm tired and disgusted by this problem. I''ve even bought a new pc for the occasion of BF3, and now to have problem for the mouse.. It's unacceptable, if Logitech will not release a fix (driver or what else) ASAP (it means in few days now) for me Logitech are DEAD products and I'll stop to give them money. 
