[Heroguy70]

The Injustice Figures go nicely with the Infinite Heroes ones... very nicely. Additionally, some of the Green Lantern figures are still available on BBTS...
NYCC 2013 Hal Jordan & Saint Walker 3.75" Two Pack Exclusive - Green Lantern Action Figures
SDCC 2013 3.75" Green Lantern 4 Pack - Green Lantern Action Figures

Sadly, the set with Kilowog is very pricey.

Most of the Injustice figures are still available and/or on clearance
[]BigBadToyStore.Com

All of these figures use a neck peg very similar to the HACKS one. It is pretty simple to pop off the head and not impossible to put a better-looking IH head in its place.Very pleased with my results on Guy Gardner. I'm looking for a suitable Aquaman head.

Aside from that Doomsday is pretty awesome. Harley Quinn is great. Cyborg is much better than the IH version, as is Raven.

Final thought about Infinite Heroes... Spectre, Wild Cat and Dr. Fate can all be customized using Boss Fight bodies with relatively little effort (getting the heads onto the BF pegs takes some patience and a lot of hot water). Lex Luthor also looks like a pretty easy kit bash, as long as you're willing to buy a couple HACKS so you can swap out color parts. They still look small compared to MU figures, but they look awesome compared to the IH versions. They even scale pretty well with the better IH figures.

Also, The Question's head can be made to fit on a MU Professor X body. He scales very well with the Multiverse/MU figures (also easy to turn into Rorschach).

Finally, the IH versions of Deadshot, the articulated version is pretty great.