I bought it, terrible idea. It's a shoddy piece of software.
I made a brief comment over on indiegames the day it came out, but essentially the game is garbage. The stuff surrounding the game is highly amusing, the music is great, the menus and videos are hilarious, but gameplay is repetitive and boring, not to mention its full of bugs.
I didn't play past level 4 because it stopped telling me what my mission objectives were, and few minutes into the level, regardless of what I was doing, I would fail the mission, but here are my impressions from the levels I did play.
The models for all the aliens are poorly done and lazy, essentially there are three kinds of aliens (in the first three levels), little pikmin dudes, green three eyed aliens that look exactly like the aliens in toy story, and blue elephants. The pikmin mob your infantry but are easy to defeat if you tell your units not to target anything. They are impossible to click on and target, so the best tactic is to just tell your units to stop moving and figure it out themselves. The other two units are essentially just artillery, you take them out with your tanks, so as long as you have more tanks than there are aliens, you win. Essentially you just fight these three types of aliens over and over using two strategies. Attack artillery aliens, or stop moving and defend against little aliens.
Then there are pickups, which are mildly amusing at first, but problematically, they are also one of your primary sources of income. They are impossible to pick up. If you are lucky the pickups will spawn on top of your unit and will be instantly picked up, but usually they spawn right next to your unit, in which case you have to deselect all your units, select one unit and then try to maneuver him over the pickup, which is usually quite difficult because units don't move where you tell them, and pickups aren't actually where they appear to be.
I could go on, but I think you get the picture by now. This is a pile of crap wrapped in some pretty amusing fluff. It'll get a laugh or two out of you, but once you get to the actual game, I'm sure any positive thoughts you have about the game will go out the window.
It's that bad.
Three thumbs down.
Everything good about this game is included in the trailers, so save yourself some money and just go watch those instead.