My experience has mostly been:
"It's fine, your teeth sometimes feel weird but that's it"
"It's stabbing my cheek a little"
"It's destroying my cheek and it has taken my appetite away"
(Top one is by far the most frequent, haven't felt bottom one in months.)
The initial recommendations made are relatively strict but they're not meant to be followed until the apparel is off, only until the 'glue' is solidified. First time I have flossed regularly, since you can't really brush the braces, although I still brush the stuff above the braces since I find anything that ends up on that area hard to reach by flossing. Occasionally the metal wire in the middle can often escape, which is how it can stab your cheek.
I also use/have also used palatal expanders, mine looking like this and this for bottom & top respectively. Generally speaking, if you grit your teeth a lot, the top expander will probably not last very long, or at least mine didn't. In a lot of occasions the top expander has to be glued to not just fall off. In these cases, eating can often become very frustrating and it will probably be guaranteed to take longer than it used to.
The bottom one is much safer from your mouth, although in my experience it can often pop out of the lower cavity while being used. You always take it off before eating something or drinking something other than water and only put it back in after brushing your teeth. It doesn't take up too much of the space your tongue occupies.