I picked up an Explorer Plus last year and used it on two canoe trips so far.  I have it paired with my I Phone and use the Earthmate app more than I thought I would have. 
As far as learning more about it.....  the most help I got was from folks from this site while at our meetings after Canoecopia last year.   I plan on bringing my unit down there again next year and badger those same folks for more info/training. I have a couple of relatives that are also a good resource.
I "think" if you decrease the tracking intervals you also decrease battery life.  I "think" the default tracking mode is 10 minutes and the 100 hr. battery life is based on that number......maybe! :-/
On a three week trip this year I only used about 25% of the battery and did quite a bit of texting.