I dunno, N900 is my first device with built-in receiver. With the previous device, an N73, i used an external BT GPS mouse (Royaltek RBT-1000 which i still own). And while that mouse is truly excellent, i.e. failed me only in NYC skyscraper ravines, in contrast i find the N900 A-GPS abysmal in both fix time and accuracying. While being abroad in Amsterdam, without network supplied positioning due to roaming, fix time was almost 10 minutes on the square in front of main station. Maybe i'm just spoiled by SiRF III w/ WAAS/EGNOS... Also the US-bought Samsung Galaxy Tab 10.1 that i had for testing until today was crap in my eyes, and with even longer fix times...