I have a neptune, I use it as an audible. Got it a few weeks ago from para-gear. I do like it, it does the job, but it does come up with some weird log data at times. I got a 490 second freefall from 14,000ft the other day! I was actually doing a CRW jump and deployed out the door, not at 2100 ft like it claimed. Here's another: exit 2900, deploy 2700, freefall 14 seconds! So I've had to delete the entire log a couple of times.
Also the freefall speeds are given at 12k, 9k, 6k and 3k and are an average over the 1000ft either side. The 12k one is straight after exit and the 3k one is right about deployment so both those are totally useless!
The average speed is usually pretty meaningless too and think is tied into determining freefall time because a low average seems to occur along with a longer than realistic delay.