Hi Lucas - for what it's worth - here's some of my own Jetfire notes
The basic design is of course, and as stated, the Valkyrie from Takatoku, and then Bandai.
I've never seen a head variant Jetfire (which of course doesn't mean there isn't one), but I have a couple of Bandai marked ones and a TT (Takatoku Toys) one at home, and they all have the regular four antenna/gun head.
Also, all the catalogues I have that show Jetfire show him with the same head.
Of course, some of the other Valkyries made by TT had different heads - my TT VF1J has just a single gun/antenna each side, and some of those other ones - the Elintseeker and SuperOstrich for example had different heads.
I've also got a '91 Bandai HiMetal VF1S, and he has a (different colour) but regular Jetfire style head.
Having repaired loads of these, I can say that they are complicated designs, but they are fairly easy to rebuild - and most parts screw together.
Hence repairs and swaps are quite easy...It wouldn't be at all hard to swap a Valkyrie head for a Jetfire, or even one antenna for another...I think Shinobi's right on the money when he suspects a custom/kitbash there!
He's also bang on with the animation explanation and history too.
As for condition and hardiness, they are pretty sturdy, as Chen says.
On the downside, their paintwork is prone to flaking in they are roughly handled, and they can suffer badly with yellowing of the plastic. This is made even more noticeable by the proximity of plastic to painted metal...
Otherwise, the armour clips can snap, and the gun clip is often missing.
Sometimes the antennas are snapped, and on Valkyrie versions, the cockpit shields are often missing.
The box is quite weak at the bottom of the window where the cardboard is thin, so tears in the bottom corners are common. Also, as the styro insert is in two pieces, the window itself often gets crumpled as the inserts are slid in and out.
As far as G1 TFs go, they are a high quality item, with very high diecast content. Personally, I think they don't quite fit with the rest of the Takara TFs - the robot design is less square somehow...but they are none the worse for that!
And given the amount of incarnations this design has had, they're not hard to find!
Although IMHO, the '91 HiMetal this was the last proper incarnation of the toy.
I know the Yamato/Bandai reissues of a few years ago were good, but they just somehow didn't cut it for me
