When I first put them in, I remember my mouth feeling SO full... like a rolled up sock had been stuck in my mouth. I was sure they hadn't been sized properly. But that sensation passed relatively quickly as best I can remember. Just don't be alarmed if that's your initial response.
I quickly gave up on the lowers. They just never stayed "glued" in and would start wobbling around after a few hours of putting them in. I have always used Polygrip... never tried another solution, nor consulted with my dentist to see if there was something better to keep them in place. So, as mentioned above, I cut apples before I eat them and can't really eat corn on the cob. Nuts are out of the question, but I'll run them through my mini food processor when the cravings get strong.
I've never had any problems with the uppers. I just pop them in water with some Polydent every night. I never sleep with them.
You'll be able to eat piping hot pizza without having to worry about burning the roof of your mouth! 
Please feel free to ask any questions. I've never regretting getting them.
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