I have totally switched to using my phone and do not carry a GPS anymore. You DO NOT have to have cell service which I cannot believe how many times I've seen this comment as it is totally false. A phone has GPS which works the same as a handheld GPS. The pros to me are less items to carry, cheaper cost since I already pay for the phone and a bigger screen than most GPS's. I use the Backcountry Navigator app which cost me $10 a couple years ago, but it may be a bit more now. I use it for camera, video, GPS, small lite, also phone and/or text where you have service. The cons are battery life, probably less durable than a GPS, loading maps on the phone may need to be done in advance, screen quality on a phone is likely lower than most GPS's. The Pros far outweigh the cons for me. Battery life issues can be minimized by using the airplane mode or bringing along extra batteries (android) or some type of charger (many types to choose from). Leaving it off when not using it also is a big help but it does take more time to start up and relock in the signal. If your camping at the road vs backpacking, the battery is easily charged at the end of the day.
Not that GPS's aren't still a good tool but I wanted to reduce the things I have to carry so for me the phone has become a new standard that accomplished what I wanted. It did take me a while to learn things as I'm not a techie. I love that I can download the topo or aerial views at no cost (I've not paid one penny for maps or chips, etc.) I think they will be only getting better with time and for me, I'll never go back to a GPS.