Progression Rates

http://www.therpgsite.com/showpost.php?p=860734&postcount=21

Obvious caveat here is that 4E is built on a level 1-30 scale rather than a 1-20 scale, but even so it's quite clear that once you hit level 5, 4E actually ends up with a much slower level progression than any previous Wizards of the Coast edition of D&D.

With 3e xp has no platonic value, 1 xp means more the higher level you get.
My experience is that 3e & Pathfinder progression rate is quite similar to 5e after the first couple levels, but the power increase per level is much more so it feels much faster. My Pathfinder campaign started at level 2 and wrapped up yesterday at level 14 after 34 tabletop sessions; 12 level-ups so 2.8 sessions/level, but in the single digit levels it was generally 2 sessions/level. Similar to 5e, BUT 3e/PF PCs double in power every 2 levels, they start feeling like demigods around level 11. 5e PCs feel much much more grounded, I'd say they double in power more like every 4 levels (faster 1-5) so it doesn't feel nearly so weird.

4e PCs double in power about every 4 levels, much like 5e PCs. XP awards look similar - it's designed around 10 standard awards to level - but the fights are much much slower than in 5e and this keeps the actual speed of progression down. My 4e campaign started at level 1 and is level 25 after 92 sessions, 24 level ups so 3.8 sessions/level. It was 2-3 sessions at low level and has been very consistently averaging 4 sessions/level for most of the campaign.

My experience is that in practice 3e/PF levels fastest and has the fastest power progression, 5e next, and 4e is the slowest.

I'm also running a Classic D&D campaign, PCs currently around level 6. It seems to be around 3-5 sessions to level (the recommended rate in the Rules Cyclopedia as I recall), and actual PC power increases more slowly than 3e/PF but similar to 5e and 4e, maybe a bit faster.