So a guy over at BGR.com got hands on the leaked iOS 4.3.1 and successfully managed to install it on his iPhone Device. Previously it was reported by them that the new iOS would probably fix a few bugs encountered in iOS 4.3 such as improved Battery lifetime and is expected to be released in Public within the next 1-2 weeks.
The guys over at BGR tested the leaked iOS and it really does fix only a certain issue which are listed below:
Baseband updates for the 3GS and iPad (original)
Fixed memory hang that results in memory corruption when reading large files from USIM filesystem
Fixed problem with NTLM authentication in apps and on websites
Fixed issue with the Springboard and 3rd party apps not recgonizing the gyroscope on the iPad 2
Fixed iPad 2 jailbreak vulneratbility