it has been a while since i was on top of technology.
what is the current recommended gps?
The latest, and the only watch among them, is the Locosys GW60. It has much higher waterproof rating than the earlier ones and many like it for it's wearing convenience.
But the older discontinued Locosys GT31 and GW52 models are perfectly acceptable and reliably accurate. Indeed, many still prefer the GT31 for it's long battery life and virtually unlimited data capacity. Both these options need a protective waterproof case of some type.
For competition or GPSTC use, nothing else is in the same class or is not allowed.
see: gpsteamchallenge.com.au/pages/rules
Edit: I forgot mention there are some UBlox based GPS devices being tested that as accurate and reliable, or more so, but they are not in general production as yet,
Silvec01 quite a few places sell the GW60 watch in Oz but the only WA stockist that I know of is Surfsailaustralia.