As a rule of thumb it's usually nice to give some indication of what your spoiler is actually about. Putting spoiler tags about something in Rogue One when the topic is Kylo Ren and TFA doesn't really warn people of the nature of what's being said.
Kind of like:
The ending of TFA was great except
Kind of like:
The ending of TFA was great except
Spoiler:I thought the twist of The Sixth Sense where Bruce Willis learns he's a ghost was better.