Terry, GMPC identifies it as COM6: BthModem0. I was wondering why Windows showed 4 different com ports, and if maybe more than one program could access it simultaneously. So I fired up OziExplorer along with GMPC. Ozi scanned all the com ports and didn't find a GPS. When I quit from GMPC, Ozi found the GLO on COM6 at 4800 baud. But when I started moving map mode it gave me a communications error. I didn't dig any deeper because I don't actually plan to use Ozi on the Slate.
For fun, I also tried nRoute (after quitting Ozi and GMPC). It scanned all the com ports and didn't find the GLO - which is, of course, no big surprise.
So I went out for a short drive down a little sand road in the Pine Barrens for a first test. First, my gut feeling is that GMPC is actually using the higher refresh rate of the GLO. In track up mode, the screen appears much more "active". If I swerved left and right just a bit, the map rotated to match - something I've never seen with my Navation USB stick. Screen updates definitely felt faster with the GLO.
Also, the touchscreen on the Slate was more responsive than usual. I think the Slate just doesn't like to have any wires connected to it, even the USB GPS. They seem to pickup some kind of RFI that affects the (lousy) touchscreen.
During this test I placed my Garmin Montana 600 on the dash right next to the GLO. Here are the satellite screens on both devices. I never really understood how to read these things, or if they can be directly compared across devices. But this implies to me that the Montana was getting stronger signals.
I set the Montana to record a track point every second. There is no equivalent setting in GMPC, so I used the "Most Often" option for recording interval. As you can see from the tracks below, GMPC is not recording points at fixed intervals like the Montana. It would be interesting to see how the 10hz tracklog compares, but I would need to find some other software for that.
I saved the track on both the Montana and GMPC, but I couldn't open the GMPC track in Mapsource; I got an error message when I tried, saying Mapsource couldn't read the Current.gpx file. Even though I had saved the track and named it "gmpc", it was not actually saved as a separate file on the Slate.
However I was able to open the Current.gpx file in GlobalMapper (a powerful GIS application), and it displayed all my waypoints, routes, the current track and my saved track inside the file. So here are some comparisons from GlobalMapper, using NJDEP orthoimagery. The red track is the Montana, the blue track is the GLO/GMPC.
Really, they are pretty much the same. If you zoom way in, there are a few variations. Just offhand, I would say the GLO more accurately follows my path.
And here I have zoomed way in on a section where the two tracks vary. Again, the Montana is red and GMPC is blue.
Here's an extreme closeup of the tracks, minus the orthoimagery. That road is quite straight, so I would say that the GLO (blue track) is more accurate.
So I'm really happy with the GLO so far. It "just works" without the need to do any special configuration. I still have not received the mat for the GLO that I ordered from Garmin. DHL says it's somewhere in St. Louis. The $10 two day Fedex from MacMall was certainly a better deal than the $8 DHL shipping from Garmin - although I will give Garmin props for actually shipping it the same day.