I had the Helite; as the bullfrog says: no subscription, no batteries, no electronics, and something like £25 for a new cartridge should you ever inflate it.
I only ever had it inflate once, when I came off at a ford.
Very heavy, but you honestly don't feel the weight when you're on the bike. Definitely warmer, though, when wearing it, as it blocks the jackets vents.
A friend has the Dainese one - also warm - and he'd often finish a ride saying he'd forgotten to switch the thing on. With the Helite you do need to remember to tether it, but you can easily check it's on while riding, and tether up at the next set of lights if you need.