a good site for this unit is www.avic411.com
I had the f-700bt which is the previous model. I had it only 3 months and just swapped it out last week for an alpine unit.
the boot time was 1 minute, then another 30 seconds or so for the bluetooth to kick in.
for me, I could not take the boot time, if for example, you shut your car down with the volume up high, then get in the car the next morning, you cannot even turn down the volume for 30 seconds or so.
the navigation was not that great imo but it was adequate, the bluetooth did not work reliably with either of my blackberries. sometimes the touch screen would not respond, or respond slowly. The unit runs windows CE, there are tons of hacks for it, unfortunatly none make it run faster. my experience was frustrating, to the point where I almost put my fist through it a couple of times, you would hit a button and the thing would beep but it would not respond.
if you can put up with the boot time, you will probably be fine, but for me, it became an exercise in frustration.
on a positive note, sound quality was very good. I paid about 500 for mine, the X710 is basicly the same unit, so if you can find an f700 around, you may be able to get a good deal on it and save some money.
good luck.