It's weird. With mobile technology, I am not as nostalgic. I usually feel that whatever is my current daily driver is my current favorite. Same applies to my favorite software. For a time, Jelly Bean was my favorite Android version until I moved to KitKat. And now KK is my fav until I try out Lollipop or Muffin. In other forms of entertainment, I always feel when I was younger was better. Like late-80's to early 90's had the best wrestlers and hip hop. My fav era of video game consoles was the 6th gen starting with the SEGA Dreamcast. My all-time NBA player was obviously Michael Jordan. I grew up on Michael Jackson and Mike Tyson. Favorites is usually based on nostalgia.
With mobile phones, latest is greatest to me. Maybe because with phones, I started late (1999) and generally don't keep them long enough to feel attached. It takes about 18 months and maybe I start to feel some sentimental value. By that time, battery starts degrading though. Only the Samsung Focus I had for only 5 months remained a Top 5 fav. My next favorite will probably be whatever next flagship I will get. I owned about the same amount of phones as the GSM Arena editor of 25+ phones since I was 19. I would say less than half of them I really liked. The others were just temp jobs or just awful devices to use even back then.
The ones I really liked -
Xiaomi Mi 3 (2013)
HTC One (2013)
Apple iPhone 4 (2010)
Google Nexus One (2010)
Samsung Focus (2010)
Nokia N82 (2007)
Apple iPhone 5s (2013), didn't have it long
MyPhone QTV28 (2011)
Apple iPhone (2007)
Sanyo SCP-5500 (2004)
Nokia 3360 (2001)
Everything from Motorola RAZR, BlackBerry Bold 9000, and whatever I owned I didn't really care for. Like many so-called friends, they just come and go. The most bearable phone for me to go back to is still the Xiaomi. I can't go back to the M7's camera and battery life. I can't go back to the 128 MB RAM from the og iPhone. Or any device without apps and Wi-Fi. My favorite ERA of smartphones is the current one. Maybe 10 years from now that tech has truly matured and the current jump isn't as drastic like graphics from PS2 to PS3 to PS4, I might look back at phones from 2013-2015 and say I can go back to using that! For now, most smartphones age like spoiled milk to me with laggy software with only a few gems you may find in-between and can age like fine wine...
Like from my generation who still praise Saved By The Bell. Yeah, I used to love watching that show when I was 10. I liked that Jimmy Fallon reunion where the S6/S6 edge has as many views at 28M. But would I watch it now? Hell no. Same with Full House. The superlatives mostly come from nostalgia.