Coming from a 3 year, 4 month old Lumia 810 (the shortest supported phone EVER, thank you T-Horrible :angry
to the 650, I am very pleased with what I got. My 810 took a NASTY fall and for once the screen shattered (it has taken
many tumbles through it's life and came back rather unscathed. Even falling off my motorcycle in a parking lot at 10 mph, watching it bounce in my rear view mirror was sickening, but picking it up only had a cracked lens which was amazing).
I just got it yesterday, and have been playing around with it extensively (trying all settings, features, etc.) and it's doing great, once I got everything updated (I did a fresh reset and set it up as a new phone, instead of using the old WP8.1 backup).
The four things I do miss, so far. 1. Double tap to wake. 2. Wireless Qi charging. 3. Dedicated camera button. 4. 802.11 ac (5gHz) Wi-Fi. The lack of Qi charging is my biggest disappointment (personally I think MS should make it a default feature on all their phones to make them stand out). But I will adapt, as I always do.
I'm one that keeps my "toys" for quite awhile (as you may have noticed on how long I was rocking the 810), and I think I will be quite content with this phone. I'm not a huge "power user" on the phone side, so as long as it does the basics well (phone, messaging, photos, OneNote), and let's me check my news, maps/navigation, and an occasional time killing game, I'm happy.
The reason for me for going with the 650 was price. I just didn't want shell out $$$ this time. I wanted to keep it $ or $$ price wise. Also, I want to hold out to see what the next cycle of phones will look like in 2017 (Surface phone?). For once I might upgrade quickly if they look good and are reasonably priced.