Sprint/AT&T
I got two of the best.
12 yrs with Sprint (my favorite of the two)
just 2 yrs with AT&T. (its free because of work)
I have more dropped calls with AT&T (and it doesnt work in my town) but I can text with that phone so I use it more. Since it doesn't cost anything, I can use their minutes for free and stay within mine on Sprint without going over.
I have Verizon with Onstar but it doesn't work very often.:(