"The a-gps is not as accurate or as fast to connect with the gps satellites"
Accuracy of the iPad's built in GPS is 20 to 30 feet. Not inches like the external GPS receivers can deliver, but close enough for navigation of a vehicle.
"I believe it will be very slow to connect"
I don't have the external GPS to compare. In my experience, the iPad gps, working without the help of cell phone tower triangulation, takes a couple of seconds to acquire its first position. Not the sort of performance one needs in a cruise missile, but for car navigation it's no problem. Once the starting position is calculated, there's no delay in keeping up.
"...probably won't connect reliably in a canyon or in trees as a decent "sirfstar iii" gps would."
Again, without direct comparison between the two, all we can do is speculate. The iPad 3G uses the Broadcom BCM4750UBG GPS chip, which is a "real" GPS chip. Undoubtedly the placement of the external antenna of the SirfSTAR GPS up close to the windshield, or even outside the vehicle, would help performance in challenging situations. I suppose if you really needed the iPad GPS to be its most accurate, you could stop and take the iPad out of the vehicle to get a reading.
A lot of the criticism aimed at the iPad 3G is made by GPS enthusiasts, who rightly point out that an external solution is faster and more accurate. The question is whether the 3G is fast and accurate enough for your particular use. In my case, I'm not surveying or geocaching, just driving. The iPad 3G works OK for me.
Accuracy of the iPad's built in GPS is 20 to 30 feet. Not inches like the external GPS receivers can deliver, but close enough for navigation of a vehicle.
"I believe it will be very slow to connect"
I don't have the external GPS to compare. In my experience, the iPad gps, working without the help of cell phone tower triangulation, takes a couple of seconds to acquire its first position. Not the sort of performance one needs in a cruise missile, but for car navigation it's no problem. Once the starting position is calculated, there's no delay in keeping up.
"...probably won't connect reliably in a canyon or in trees as a decent "sirfstar iii" gps would."
Again, without direct comparison between the two, all we can do is speculate. The iPad 3G uses the Broadcom BCM4750UBG GPS chip, which is a "real" GPS chip. Undoubtedly the placement of the external antenna of the SirfSTAR GPS up close to the windshield, or even outside the vehicle, would help performance in challenging situations. I suppose if you really needed the iPad GPS to be its most accurate, you could stop and take the iPad out of the vehicle to get a reading.
A lot of the criticism aimed at the iPad 3G is made by GPS enthusiasts, who rightly point out that an external solution is faster and more accurate. The question is whether the 3G is fast and accurate enough for your particular use. In my case, I'm not surveying or geocaching, just driving. The iPad 3G works OK for me.