Overall, a good game.
Path of Radiance, however, suffers one major problem in the transition to 3D- it became annoyingly bland. To provide possibly the most jarring example of this, Joshua, "The Sacred Stones"' Swordmaster, is capable of critical hits - for him, that means fading back into five translucent Swordmaster sprites, weapons drawn, each of which strikes the enemy one time then melds back into the real Joshua, who does the damage. Stefan, this game's Swordmaster, simply runs forwards and hits five times, lacking the ability to draw excitement that Joshua's sprite-based assault did. The graphics in the game don't exactly push the envelope for the Gamecube either. Though they're certainly bearable as games go, nothing truly made my jaw drop as I played.
If you liked one or both of the GBA Fire Emblems, I suggest you rent this one to see if you like the changes before buying it. If you don't but have a passing interest in strategy games, Advance Wars, Marth, Roy, etc. buy this one and go back to the Gameboy games afterwards.