well if you want me to tell you what should be in your collection out of those particular 3 then I say go with power battler junkheap just because of this:
"as a
tail-ender for the Power Battlers assortment, Junkheap eventually fell victim to "tail end of the line" syndrome, and wasn't officially released until
much later than initially planned, not helped by a
massive slowdown at US West Coast docks caused by union action. Thus far, Junkheap has only been available in Hasbro's Asian markets, from online retailers and discount stores like Ross, T.J.Maxx and Five Below. To make matters even
worse, he is only included in one wave alongside the other two new Power Battlers figures,
Vehicon and
High Octane Bumblebee, while a revision of said wave that includes Vehicon and Bumblebee but lacks Junkheap was actually stocked by online retailers
first, with some never even bothering to list the wave that includes Junkheap. This sculpt was also used to make
Adventure Junkion."
http://tfwiki.net/wiki/Junkheap_%28AOE%29
I'm a big fan of rarer hard to find figures eh and if that floats your boat then there you go