Define your needs, homie.
Are you gonna record everything yourself? Do you want GREAT quality or just a sketchpad? Do you need great editing capabilities? What the hell are you doing???
Okay, the 414 is better than the Porta2 cause you can record on all 4 tracks at once, and it now comes with a built in DI and a Mic input. Plus it records at double speed meaning a cleaner recording.
But the 424 has 6 channels (still only 4-track), the option to record and normal or double speed, Auto Locater functions, etc.
It really depends on your needs though.