I have a Samsung Galaxy S5 and I LOVE it! The screen is pretty invisible if you are outside with polarized sunglasses on, but aren't they all? Anyway, I love the size of the memory (room for lots of apps,) the size of the phone (not tiny, but small enough to tuck into the outside pocket of a purse,) and its relatively intuitive design (both the hardware and software.)
I think the reception has more to do with your carrier's coverage than the phone, but I am not totally certain that the phone doesn't play a part.
I am an AT&T customer and I really appreciate how the staff in the stores will help you if you have a problem, even long after you have purchased the phone. Maybe all the carriers have similarly helpful staffs, but they DO NOT have identical coverage. If you need to use your phone in rural areas or know your home gets iffy reception, best to compare coverages before deciding which carrier to go with.
Good luck!