[Samsung Galaxy S21+] varcor:
Like everyone else whether a device is an "upgrade" comes down to preferences, useful features which make a difference. Price is a consideration but not an issue if the device stacks up. Trade-in promotional pricing doesn't motivate me for a number of reasons. First off, I don't want to deal with carrier bloatware. Secondly, I don't care to enter into a muli-year commitment with any Service Provider. Lastly, all US Galaxy variants are bootloader locked.

My daily driver is an SM-G9750, S10 Plus, Hong Kong variant. I would enjoy Snapdragon's latest SoC found on the S21 but that's not saying the S10 Plus is slow, it's not. A larger battery is also appealing but I'm pretty sure I'll still need to charge the battery once a day. The cameras on the S21 Plus are the same as the S20 Plus and the only difference from the S10 Plus is a bit larger appiture. 5G is in it's infancy but at this time many of the useful iOT it will enable aren't yet available. Additionally, many 5G users state it's not much faster if any, than a good 4G pipe but at this time for device manufacturers and service providers 5G is a goldmine, the greatest marketing scheme since light beer. Based on my preferences these are issues I have with the S21 Plus.

1) No MicroSD. Sorry but I have zero faith in Cloud Storage, not only for data security but privacy as well. Samsung has also reduced internal storage capacity. 256 GB isn't enough, I have to close double that amount on my MicroSD already and adding more every week. It also saves time when you need to transfer data to a new device.

2) Camera Housing. The S21 camera module is an improvement over the S20 which is awful. It blends into the frame a bit better but it still doesn't lay flat and will snag coming in and out of pant pockets. It also degrades the device's symmetry. Samsung has like many of their competitors have gone overboard with multiple lenses. I'm certain if you had a photo from an S10 and another from an S21 side by side, you wouldn't be able to tell which device created the snaps. That's the trend in mobile phones but if you want really great photos, use a camera not your phone.

3) 3.5mm Jack. Wired audio is the gold standard, Bluetooth doesn't compare and who wants the hassle with charging buds? Yes, I can buy new earphones with a USB connector if I don't want to use a dongle but then I can't charge my device while listening to audio files, which I do often. Plus I really like my earphones, they sound great!

3) Flat Display. I like the look of Immersive Displays. I do a lot of gaming and watch a ton of movies or videos. A curved display doesn't bother me at all.

4) Size. The s21 Plus and Ultra aren't pocket phones. They're huge, closing in on tablet size, just too big! I prefer a device I can easily slip in and out of my front pocket. If I went with an S21 it would fit well but sacrifice a number of features.

5) Screen Resolution. Not sure in most instances if I could tell the difference between 1080 X 2400 and 1440 X 3040 Pixels but why downgrade on an "upgrade"?

6) No Earphones or Charger. Not my biggest issues but then again isn't the S21 Plus supposed to be an "upgrade" over my current device?