What would be easier AND most importantly, the reliable option to update my iphone and jailbreak it again?
Many factors to consider. Your own personal choice will have to be governed by the different variables that you are going to have to sift through. But here's the rundown:
Easiest (as in, less effort) would indeed be to update to official Apple firmware and then to use either blackra1n or redsn0w. But like I said before, you lose your older baseband firmware.
Why would that matter if you're not planning to unlock? Well, for one, it certainly wouldn't hurt the resale value of your phone if you decided to keep the old baseband around, that's for sure. (Your phone can still be unlocked if you upgrade the baseband using blacksn0w, but then you run the risk of WiFi and other problems.)
blackra1n vs. redsn0w? Well, again, if we are using "easy" as the measuring stick, I think it would be hard to argue that other methods are easier than blackra1n currently. After all, it only gives you a single button to click on when you load it.
redsn0w gives you more options than blackra1n, but the version that supports OS 3.1.2 is also still in beta/not officially released, and the Dev Team is still sorting out minor problems with it here and there and updating the beta gradually as that process moves along. I'm sure they will have all the kinks worked out soon enough.
PwnageTool gives you an option that no other jailbreak method gives you: a way out of upgrading the baseband firmware, and electing to keep the old one. I would say that PwnageTool is not difficult to use, but in comparison with the other two methods, the level of difficulty is admittedly higher. First, you have to have a Mac, since there is (as of yet) no Windows version of PwnageTool. Second, it's not just a matter of clicking through a Wizard or hitting a button and having it do everything in one fell swoop. You have to have a copy of the firmware file handy, have enough free space to generate another (custom) one, let PwnageTool run the necessary exploit for your phone depending on the model and whether it has already been jailbroken before or not, and then you need to load the custom firmware into the phone using iTunes separately.
So, ease-of-use-wise, I would say the order, from easiest to more difficult, goes like this:
1) blackra1n
2) redsn0w
3) PwnageTool
But benefits-and-flexibility-wise, the order goes in exactly the opposite direction, with PwnageTool on top.
I personally use and recommend PwnageTool, but if you want to make things the absolute easiest on yourself as possible, and you have read and acknowledge the disclaimers about your baseband getting updated in the process, then use blackra1n. If you want something still somewhat easy but with a few more options and flexibility than blackra1n (but something which will still require you to go through a baseband update), use redsn0w 0.9beta3.
I hope this has been helpful.
-- Nathan
