I am looking at buying this computer for my wife solely for the addition of the GPS. I am Very interested to hear more reviews on the computer and the GPS (lack of) performance. What I envisioned initially is diving in Bonaire - mark the start point, swim at leisure at depth, turn the dive and ascend to a shallower depth and surface & exit at the point of entry without having to do a surface swim. Hopefully that's not too much to expect for what is advertized.
That's not going to happen. GPS signals don't penetrate water very well. What you envision might only be possible on a surface swim. In addition to a Perdix, I also have a Garmin with GPS. Garmin has been at the GPS game for a while, so have it pretty well dialed in. I definitely don't have many of the issues reported with other GPS enable dive computers. Even then, it doesn't do what you are asking.
I can get the entry and exit points of the dive, but nothing in between is logged, which is to be expected. Garmin does have a "Reference point" feature, which is to guide you to a particular point on the surface, but I don't use that.
I really only use the GPS to mark a location. Prior to getting the Garmin, I used my iPhone's location to save to the Subsurface log. Since I got the Garmin, I don't do that anymore, I just use the Garmin location. It's a convenience only. I definitely wouldn't say it's a must have feature.
I'll get her the Shearwater Perdix 2 if Ratio doesn't deliver. Thanks for any further information!
Looks like she'll be happy with a Perdix 2. Honestly, as I said above, you can pretty much do with a non-GPS computer and a smartphone what you can do with a GPS enabled computer. If you use an electronic dive log like Subsurface, MacDive, etc. they usually provide a means to log the location either directly by using location, or by allowing you to paste coordinates in. You'll only have a single location, but for the majority of divers this is fine.