I never understood the hate for 'green bubbles' either. I only see one advantage iMessage has over SMS, and that's working on wifi, no cellular service needed.
That being said, I prefer SMS. You don't even want to know the fights that iMessage 'features' caused me and my girlfriend, who lives in another state. That 'typing indicator' and 'your message has been seen' have caused more misunderstandings than I want to remember. From it showing her 'typing' when she wasn't, me assuming she was ignoring me because my message was 'seen' but not responded to, the works. I'd had given anything to disable those 'features'. As for 'group messaging,' another advantage they cite--I always hated those, especially when I was big into Facebook ~ 2010. I would get a text, assume it's from my girl, and it was a group chat I got added to and I had a heck of a time getting out of. I can't think of one situation where group messaging would be anything but an annoyance.
All I want to know is if my message got sent successfully. If there's a response, my phone goes off and I get a notification. Why complicate it?
SMS does exactly what it is supposed to, with an intuitive layout. It doesn't require data at all, just bars (which is 75% where I live, LTE just sucks here in Owensboro, KY.). It might be old, but if it ain't broke, why fix it? It has a very IM-style layout which is far superior to the long-outdated mess it was on the RAZR VIII.
I don't see the whole 'compressed photos' issue everyone remarks about. Every picture I send seems to not only preview properly on my end but I have yet to get any commentary about 'potato-quality photos'. Also, I don't have to constantly get into an upgrade loop because apps such as WhatsApp get disabled or cease to work if your OS gets too far out of date. Since I don't give a darn about updates I'm safe using SMS and knowing it doesn't need me to keep buying a new phone which is already an issue worldwide if you factor in e-waste. I'm striving to get out of the consumerist mindset so apps that depend on the internet or the latest OS version aren't for me (also don't forget WhatsApp is owned by privacy-hating Facebook)
Also, I don't have to be sure all my contacts install the same app and use it. That would work wonderfully with my 94 year-old grandmother who barely fathoms a smartphone at all, much less switching from SMS which is familiar and easy to use to something foreign. The disadvantages outweigh the advantages in my use case.
For myself, having to install some app like WhatsApp, Line, Telegram or the like feels like going back to the 1990s when AIM, ICQ, Yahoo! Messenger, and Windows Messenger were big deals--including being built-in to feature phones at the time. I had a Samsung flip phone with Yahoo! Messenger built in, but never used it since only one of my many contacts had access to it.