I've been using this phone for 6 months, I can personally attest that the gps performance without agps is very erratic. I use the gps for fun, but for some reason it works in some really worst conditions and sometimes never locks in on open sky clear day.
I got myself a Holux 1000c bluetooth gps (<RM200) from ebay they pair OK, works with OVImaps, garminXT. I love this phone!

Just some of my input.