There's a lot of similarities between the two, actually. Not just in sales trends, but in design decisions and end results as well. Both relied on a "better" screen and "more" controls than their competitors, as well as a more impressive sound processor, at the cost of battery life. Both have a larger physical size and weight than their direct competition (though not by a huge margin in either case). Both have screens noted for having ghosting issues. Both were marketed as a "better option" to the Game Boy line. Both prominently featured ports from previous systems and were similar to those previous systems (the GG is basically a beefed up portable Master System; the PSP is basically a beefed up portable PS1). And both garnered less than stellar software sales (in that regard, though, Game Gear actually outclassed the PSP, mostly because pirating GG games was not at all easy in the time of its market presence).
Sky Render - Sanity is for the weak.
