The problem with the spin offs is that they're clearly done from (at best) very early scripts and outlines and often mesh up only vaguely with the final films. For instance, the prequel comics to the second film had a whole thing about the Fallen being trapped in a mysterious stone that isn't in the finished film at all. And that's one of the more minor ones.
The IDW comics also suffer from being made by people who clearly don't like the films very much and are making a clear concerted effort to force everything into the G1 style. So for example,
Reign of Starscream completely ignores the deadly, competent and seemingly loyal quick sketch characterisation he had in the first film to just do Chris Latta redux. Not to mention the whole thing being made redundant by proper sequels anyway (and hilariously Starscream's characterisation changed to being a completely incompetent comedy stooge who's just as hard to picture in the Reign comic).
Now, fair enough lots of people don't like the films, but if you're actually going to do a comic based around them you should at least get a guy who enjoys them, or at a minimum sees the potential in what's a good set up for a comic. It's not as if IDW don't do a buggerload of G1 comics for people who'd rather be reading old school stuff.
It means that it's almost impossible to tell if Shockwave's large role as basically Dreamwave G1 Super Shockwave was all a cunning part of the misinformation campaign about the real villain before the film came out, or just a sign of them not being given any info bar a picture of him (and indeed, the G1ish art suggests they didn't even get that) and creatively bankrupt recycling of old ideas went on.
And personally, I found
Ghosts of Yesterday to be terrible (and can be happily skipped as all the space stuff is cheerfully impossible to reconcile with the third film). My review of it is here:
http://tfarchive.com/comics/idw/review.php?s=movieprequelnovel_a
