Welcome to the forums.
Right now the untethered Jailbreak is......troublesome at best. Search around the forums here and you will find that out for yourself.
For now all I can suggest is that you upgrades in increments. Upgrade to all of the betas one by one, jailbreak, and save your SHSH Blobs in each beta. You will NEED the Beta 3 one in particular in order to use the current untethered jailbreak ( which as it stands right now....is a failure until they release the official one )
I wish you good luck.
Not the best advice digikid. There is no advantage at all in upgrading incrementally using the beta firmwares. You are misunderstanding the process for saving blobs. All you will do is waste the time of the OP.
Firstly, there are no blobs for beta firmwares OTHER than beta 3 which was a special case (it was supposed to be the release candidate).
Assuming the OP started saving blobs through Cydia with 3.1.3 then they can retrieve all their blobs from Cydia using tinyublrella. It is irrelevant what firmware you are currently running, and you cannot generate blobs for your current firmware if Apple are no longer signing them. He either already has blobs or he does not.
If you did not save your blobs (you can tell by looking at the top line in Cydia. It will tell you what it is storing for you) then you are out of luck and can only get 4.2.1 at the moment.
The tethered jailbreak is also not as bad as some people are making out. I certainly wouldn't' describe it as troublesome for someone that is comfortable with jailbreaking devices.
Whilst I started with the position that I would not recommend it a couple of months ago (because of my prior experience with a tethered iPhone jailbreak), in practice I have only had to reboot my iPad twice and therefore the tethered nature of the jailbreak has been almost imperceptible to me and many others. I would now recommend it.
The tethered jailbreak itself is bug free. That is not to say that Cydia apps have full compatibility with 4.2.1 yet, however the vast majority do.
Hope that helps.