I would update to 4.3.3 if I were you. At this point, you might as well enjoy all that iOS4 has to offer, as 5 is right around the corner. It's extremely easy to jailbreak with either redsn0w or pwnagetool. Just note that if you plan on preserving your baseband, anything above 4.3 will screw up the signal bars and show 1 bar no matter what the signal strength. installing ultrasn0w can fix the issue, but it is known to also mess up your MMS/Visual voice mail periodically.