This game looks cool (specifically that bombardment model and mechanic), but I am wary.
I am interested in game length, balance, and "take-that" card aspect. Thanks.
I haven't played Android, so I can't speak to how it would compare to that game. Adam has already mentioned that Rex is similar to Dune, what he may not have been perfectly clear on is that Rex is actually an official remake of Dune, with a different setting. The two games are not identical by any means, but they are 90% the same, I would say. So if you want to know what Rex is "like," go read the reviews for Dune on BGG and you'll have a pretty good idea. (I personally recommend the "Finally, a game for jerks!" Dune review. I think it captures the game dynamic nicely.)
As far as game length goes, Rex stops after 8 turns compared to Dune's 15. It also has increased movement allowances and basically incorporates the "double spice blow" advanced rule, which means both money and troopies will be flowing faster in a game that ends quicker. I can't really give an accurate time estimate on Rex since I haven't played it yet myself, but I can say with confidence that this will not be 6 hour marathon like Arkham Horror or Descent. Certainly not as long as TI3.
The cards in Rex are composed somewhat differently than they were in Dune, and by and large I'd say they downplayed the "take that!" aspect of playing them. Most of the cards in Rex have a tactical advantage for you, rather than a sudden penalty for your opponent. The notable exception is traitors, which I suppose would qualify as a "take that!" and, to be fair, traitors are an integral part of the game. You COULD simply play without them, but it wouldn't be the same.
As for game balance - that depends on what you mean by "balance." The factions are asymmetrical as all get out - they all have unique abilities that are completely unequalled (Hacan receives payment for everyone who ships units down from orbit, Xxcha can command his opponent in battle not to play one specific card of his choosing, etc.) Intra-player diplomacy plays a strong role in Dune, and I expect it will in Rex as well having read over the rules. How well balanced the game feels will rely strongly on who you're playing with and how well a player can leverage his own faction's resources. This is definitely not a game where you can just sit back and coast through your first few plays - if you have any great desire to win, that is.
As for Munchkin, the only thing Rex has in common with Munchkin is a deterministic combat system, and even then the similarities lie mostly in the definition of the word "deterministic." There are no overly large enemies that you need to team up against (unless one player is making himself such.) Everyone has the same number of units to bring to bear - except Lazax who has a small number of slightly stronger units.