yep strava app works on many other phones.
oddly i cant find many references to GPS issues with ICS upgrade - what i see is tech folk saying its the how the chipset is implemented into the phone that causes the issues.
So unless ICS removes the chip and puts it in badly then its a known issue with the s2.
FWIW my iphone 3gs and 4 used to track nicely.
my edge 205 and forerunner 305 were a bit more sporradic
my edge 500 you can see exactly what side of the road i rode down.
as i said before your other apps dont need every second data points so it can disguard erroneous data points that are clearly gibberish.
but if your convinced your phones so great - crack on , it doesnt effect me. Cant help the unhelpable.