I was using both: A Samsung Galaxy S5 on Straight Talk for most of my home phone calls and data use for work, using it as sorta a micro-tablet for PDF service manuals, and my iPhone 6S for CarPlay, mobile use, Apple Pay, Watch, etc. everything else.
Recently, as in the last month or so, SMS messages are failing 99% the time from the iPhone and my Apple Watch. It should be using iMessage and forwarding as SMS any message to any contact not using an iPhone, but that part has been failing so often (iMessage itself is fine, but my Girlfriend lives in a Covid-19 hotspot and communication with her is something I consider vital and she uses an old Android phone) that I have been forced to grab my spare Motorola G7 Power phone I keep as a backup (one among many, unlocked and compatible with T-Mobile, which is the carrier my iPhone was using) and swap the SIM card into it to maintain communication with her. Yesterday I literally couldn't send a SMS to her period, at all. It came back 'not delivered' and my watch and phone both. Sometimes I could get replies or messages from her, but repeated 8 times in a row. She says her messages to me fail as well.
That has not happened since re-activating my Motorola. Despite how much I hate how big it is, it does sport a huge battery, and while modern gesture-driven Android isn't quite my forte, I did at least theme it before I went to the iPhone, so it's ok for now. It kinda sucks I can't respond to an SMS via the Galaxy Watch paired to it, since Samsung disables the messaging and certain other apps from working with non-Samsung hardware, but I suppose it's more important I can talk to her over which device I use to talk to her.
I really have started liking Apple again after my initial disgust when iOS 7 came out (which diverted me to Samsung for 6 years) but lately their software even if you don't update it to avoid bugs, gets buggy. I rebooted my iPhone a dozen times over last week for various issues from SMS failings to it showing 'no service' and never recovering, to a recent issue where it wanted my payment info for zero reason (that notification never went away either). I have no clue what happened to the 'it just works' I have grown accustomed to but it's apparently dying off over at Apple. My Mac won't go to dark mode on its own most of the time, and my iPad incorrectly claims it's full when it's not even halfway used up, and my iPhone won't SMS anymore.