I replaced my solar garmin instinct with the Forerunner 965. For the most part, the battery life didn't change. I'm still going through the settings and tweaking everything the way I like it. Soooo many settings... I've done multiple 70+ mile rides with this watch over 8+hours of active use and a ride like that typically takes the battery down 30% or so for me. Otherwise I'm liking it. I don't think it has any other real advantages over my last watch as it's still the same Garmin software running.
I chose to buy the Garmin Edge Explorer 2 because I wanted a bike computer that can display maps for navigation and that integrates with a Garmin Varia rearview radar, but that doesn't need to include the advanced training features that the more expensive Garmin units do (as I personally don't care about that).
So, for those purposes, this bike computer works well enough.
I wouldn't say it's perfect, though. The user experience is a little clunky. It kind of reminds me of cheap Android smartphones from 15 years ago, which is a little disappointing considering the Edge Explore 2's price.
After 7 years of usage. I decided it time to order another pair for both of my road bicycles. When they started needing close to an hour to fully charge. As to the many years of 10 minute fully charged time. But the originals still last 6 hrs on low strobe. Just hedging my bet? But rain or shine they have been worth every penny knowing they have my backside. People have commented they'd seen me from miles away. On our back country gravel shouldered county roads. Comments like that make me smile. Even on shouldered highways. Vehicles tend to give me a half a lane or at least 3 feet. So the Blackburn DayBlazers are like a warning beacon for my safety.
The Edge 840 is a really good GPS computer. I purchased this after my Wahoo Roam started being unreliable. The detail and capabilities of the Edge are superior to the Wahoo. I do most of my riding solo and the LiveTrack on the Edge provides much more detail than the tracking on the Wahoo.
The one negative I can think of is that the setup and menus on the Edge and the Garmin Connect app are WAY to complex. It seems like any sort of configuration change on the Edge is buried three layers down in the system menu.