I would have said map & compass then GPS and phone for backup, but for most of my recent walks, I have used Oruxmaps on a larger screened 7" tablet and usually with the digital version of the paper map I am carrying. The larger screen device is handier than a small GPS screen and the touch screen is easier to zoom in/out and generally navigate digital maps. So mine is now more a phone GPS and Garmin GPS and maps as backups.
I used my tablet & Oruxmaps combo with success recently in NZ, and I didn't pull out the printed paper maps I had for the entire 200km trip. I was quite impressed with the battery life of my tablet running Oruxmaps. Oruxmaps was running the LINZ maps
viewtopic.php?f=21&t=22380 and it was great.
In some cases, I've gone back to carrying my smaller lighter eTrex 30 as a backup rather than the larger Oregon 600 as a backup GPS if I am also carrying the tablet/phone as the primary GPS. I'll still carry a map as a backup though.
Of course, like all things electronic, the tablet and GPS can fail as well, or batteries die, but so far with some redundancies, it hasn't happened to me yet. I have recently lost my Suunto compass somewhere though - it must have dropped out of my pack at some point, and that's been annoying. I always have a cheaper oil filled compass attached to my bag, but I liked my Suunto.