If you're not already a fan of the series you won't be won over by this clunky installment. With an enhanced sequel coming out later this year, there's no reason to fuss with this eight year old PS2 game!
As a reminder of what came before Armored Core 3 Portable is effective. As an actual game though, it's far less so. We've simply moved on, leaving this a relic of the past that lacks the hooks it once had. Time for AC4 Portable.