My Samsung Galaxy S5's messaging app has a quick-response feature that will cause a new message to pop up on the screen, regardless of lock status, a lot like the app 'Glowfly' used to before 4.4 removed the ability outside apps used to have to mark messages as read. I'm currently running Lollipop but this was an issue as far back as Kitkat; before that, I used Glowfly.
(On a side note, if anyone knows a cheeky hack to replace this functionality, please do let me know; my device is rooted and I'm not aversed to modifying system files if it guarantees a result.)
You can respond to messages that appear in the quick-view window, but the responses are always sent as text (160 character limit) which is fewer characters than a Twttr feed. Is there a way to configure the Messaging app to send quick responses as MMS or to place splits in automatically, like using the full client does? It seems like a ridiculous oversight, but it's present in 5.0 and has been since at least 4.4, so it's either something nobody's looked at or a deliberate decision.
I quite like the stock Samsung messaging app (read: I hate all alternatives because they're gawdy, spammy or otherwise full of bloatware and nonsense) but I'm open to alternatives provided they can solve this issue. Bear in mind before suggesting a replacement that AFAIK apps outside of the stock Messaging program can't mark SMS messages as read (hence why I'm not just using Glowfly). Naturally any suggestions will need to be able to circumvent this issue.
Finally, please don't explain to me the nature of the Short Messaging Service or just suggest I make my texts more concise. I'm looking for help, not advice.