I too use iSailor and have not had an ounce of trouble with the internal GPS, nor have I had any complaints from customers who use 3G iPads. I also own a Bad Elf, as back up, but don't use it. I have had many times where we have been way out of cell range and the internal GPS works perfectly.Mainsail,
My iPad is not connected to a celluar service but I found that the internal gps (it is 3G) does not play well with iSailor. You are correct about having a second item to drag around being a pain. I did experience the loss of my Bad Elf because of the Apple IOS upgrade. Not that it makes any difference now but mine is a 3G iPad so your statement is not entirely correct. The outage lasted 8 weeks. It was an oversight by Bad Elf and Apple. We actually were out when it happened. Works great now. BTW I see that Garmin now has put out a new GPS called GLO that works just like the Bad Elf.
I also have numerous customers who cruise full time using 3G iPads with no external GPS. One of them spent three months in Newfoundland and Labrador and 90% of the time was out of range of both cell and wi-fi. He used his iPad aside his Garmin and claimed that other than one over heating event it worked as accurately as his Garmin.
What issues did you have with iSailor and the internal GPS?