After five years using the original SPOT (below), I've now upgraded to the new SPOT 2 (above).
It's definitely a worthwhile upgrade. I found a great deal online at Best Buy, even though it's the silver rather than the orange version (apparently, orange sells 10:1 over silver), but when you're saving around $70, silver's just dandy.
So, what's better? First, the weight. The new version weighs 147 gms (5.2 oz), while the old one is... quite a bit heavier. I'm carrying it on the deck of my kayak, so the weight doesn't really affect me overall, but if I was an ultralight backpacker, every gram makes a difference.
It's also much smaller, thus taking three (lithium) AAA batteries, rather than two AAs.
But what I really love about the new SPOT 2 is that you can have your Tracking on and still send an OK message at the same time, and this year's Everglades Challenge has a new rule that we need to send an OK every 4-6 hours (for insurance purposes).
With the old SPOT, it was a 20 minute process--try this at 0200 after you've been paddling for 18 or more hours...
You can't send an OK message if the tracking in enabled, and you can't go back to tracking mode immediately after pressing the "OK" button. To send an "OK" the user must first disable tracking mode. This is done by either restarting the device (off and then on) or by holding down the OK button for 3-5 seconds--in which case 3 blinking red LED and then a solid LED indicate tracking mode is turning off. Once tracking is deactivated (or the unit restarted), the device is in standby mode with only the power LED flashing. Now the user can press the button to send an "OK" message. It often takes 10 mins to transmit the okay message (in triplicate) and SPOT International recommends waiting 20 minutes. The SPOT device attempts to send the "OK" message 3 times: the first one usually is sent out during the first minute (you can tell because the OK LED goes solid for a few seconds). Once the three attempts have been transmitted, the second light stops blinking and the SPOT returns to standby mode. So, now with the unit back in standby with only the power light LED blinking, you know you can now activate tracking mode. Alternatively, to ensure that the "OK" was sent, the recommended method is to wait 20 minutes after pressing the "OK" button before activating tracking.
Get my drift?