I'm about to start two new 5e campaigns, and I decided to use a completely different XP system, almost identical. Basically the idea is 1 XP per significant encounter or achievement, such as a quest completion or big treasure haul, 2-3 XP in exceptional cases.
1. For Princes of the Apocalypse running for ca 5 hours 1/4 weeks, initially 5 XP 1st to 2nd and 2nd to 3rd, then 10 XP/level.
2. For Primeval Thule running for ca 3.5 hours 1/2 weeks , a flat 10 XP per level, but I am giving PCs a hit point kicker at 1st level (hp = full CON + max hd, rather than max hd plus CON bonus) so they can stay at 1st level for longer.
This will resemble the fiat 'milestone levelling' suggested method, but I wanted a bit more structure than that, and one better suited to sandboxy play. I'm looking for about 2-3 sessions of play per level (10 XP), which is the 5e DMG suggested rate, but much faster than in my current 5e games, which use the standard XP rules.
Discussion here
