By the way, 5 minute tracking is available on Gen 3 Spot at no extra cost. You have to configure your tracker using the web application to turn it on though. Gen 3 Spot now also does altitude on glideport.aero and the SSA site, although not on Spot's own site.

My experience has been that the Gen 3 reliability is better than Gen 1 and much better than Gen 2. Point dropouts are not that common. On the newer Gen 3 units, altitude seems more reliable than on older ones.

So with a newer Gen 3, I'm getting 5 minute tracking and altitude for about $225/year, including all fees. For me, this is worth it because I use it 12 months.