MTBing since 1980s, First proper MTB was Orange P7, then several (because I kept breaking them) Saracen Kili Magnesium frame bikes for summer, with an old Orange P7 modified to take a 8 speed hub gear for winter use. Eventually ran out of Kili frames, so got a Cube frame, which was modified to 1X9, (now sold) also got an Orange Sub 5 3X9 bouncy bike ;-) Currently ride a Orange 5 Evo in summer when ground hard, hub gear P7 for winter as it's bomb (& mud) proof, also have a basic Kona with rack & panniers for town use. All my MTBing is done with my wife, who is similarly fit and has a similar range of bikes. :-)
We don't worry about hills, we aim for at least 1000ft of climbing for each 10miles traveled or (300m for every 16km), which is relatively easy on the S. Downs where we live.