Which phone should I buy?

I'm currently using iPhone 6 and was planning to buy iphone 8 when it releases. But now I'm fed up with iphone 6. Recently Samsung also launched it's S8 and Blackberry came up with keyone. I think I should go for KeyOne because I have problem of sweating on my palms more often and that irritates me on my phone when touch does not responds. So I thing KeyOne will help reducing that by physical keyboard and also it's a smartphone.

What do you all think?

Waiting for valuable suggestions…

Will a Virgin Mobile iPhone work on Sprint?

I was gonna get the iPhone 6 Plus from sprint and use their 60$ unlimited plan but the 6 plus is 500$ new whilist on virgin mobile the iphone is 200$ preowned https://www.virginmobileusa.com/#!/shop/phones/apple-iphone-6-plus-16GB-pre-owned/features/Gray/ so I was wondering if I could buy that iPhone 6 Plus from Virgin and once it arrives go to a Sprint Store & have them activate it for me on a post-paid plan.

Will a Virgin Mobile iPhone work on Sprint & Boost as well?

The phone in particular is https://www.virginmobileusa.com/#!/shop/phones/apple-iphone-6-plus-16GB-pre-owned/features/Gray/ I got a new sim card for my current phone and I noticed on the card it had the boost & virgin mobile logo on it so I was wondering if I buy the 6 plus from virgin & it comes with a sim card can I just call Sprint & have them activate it as a new phone on my family plan

Slept on top of iPhone charger?

Last night I forgot to take my phone off the charger and I rolled on top of it, so it was under my stomach all night. Can this affect me in any way?