Hi,
I picked up a pair of Swatch SCUBA Fun Watches for the wife and myself last Christmas.
They worked just fine, and in fact saved one dive excursion when the computers failed (flooded after battery servicing prior to trip ... very odd, since they were tested in the shop pressure tank after servicing, then by us in a pool equipment checkout splash party, but that's another thread ...). Depth and bottom timer functions worked servicably well to do the two dives on that boat run with tables (which we consulted prior to the first giant stride, and which discipline paid off that day!).
Swatch says they are not SCUBA instruments because if they were sold as SCUBA instruments, then that may increase their liabilty exposure. Not to mention they are almost certainly not built and tested to the standards one might wish to have for equipment one stakes one's life on. They do advise not pusing the button underwater so as not to increase risk of flooding, for example.
They will replay your last dive (running the hands at fast forward through the time and depth profile), and you can save one dive in persistent memory in addition (sort of a souvenir). In that sense, unless your dive computer can replay the dive profile itself (i.e., without uploading data to a PC; our Suunto Mosquitos can do this, but our original cannot), then it's useful for an immediate playback of the profile.
They are kinda cool and probably fine as a cheap backup instrument for simple recreational diving, my opinion FWIW. We have tended to carry them less now that we have two computers each (the original, which was replaced without question by the manufacturer; and the replacement we rented then bought on the trip), though I will still pop it into the luggage for a long trip just to have yet another line of defence in the old save-a-dive bag.
Cheers,
W
