Yeah, here's my thoughts on the pair:
Cavalier:
-Seems to be pretty solid (d10 HD, full BAB, 4+int skills, all martial weapons, shields and heavy armor, good Fort save), I'm disappointed that there's no taunt ability built in like the Knight, but on the other hand there's a lot of customization among the orders. Having the mount built into the class from 1st level was a good move though. 3rd level is probably a good dip point.
For those who haven't seen the preview, it's basically a fighter shell with more social skills, a built-in mount, and scaling att/dmg bonuses against a foe you call out, as well as different oaths you can swear for slight benefits. Very much in the flavor of Sturm from Dragonlance. There are several different paths, like the sorcerer bloodlines, called orders.
The one that caught my eye was the Order of the Shield - the 8th level ability grants the Standstill feat and lets you make an attack that deals normal damage and still stops the opponent, which kicks ass; while the 15th level ability lets you and your mount move up to your speed and make an attack as an immediate action, then you're staggered for one round. It's like a melee celerity!
The Order of the Sword is the other stand-out - adding your mount's strength to your own on a charge can give some solid low-level damage potential, and the Knight's Challenge is a pretty hefty boost to damage 1/day.
Overall it looks solid, but I'm not sure if it competes well enough with the paladin class.
The Oracle:
It's essentially a divine sorcerer using the cleric spell list (d8 HD, 3/4 BAB, 4+int skills, simple weapons and armor, good Will save), with special paths ("revelations") that give customized spells and bonus abilities. Every oracle has a special curse, which is a little like a 3.5 flaw: for example, you're blind beyond 30ft, but you gain darkvision and eventually blindsight.
I'm hoping dearly for a Summoning path, but the preview only had the 4 elements and battle (what, not Heart?) revelations, and Battle is where it is all at in the preview. Most of the revelation abilities are usable 1/day+1/5 levels, which I'm not a huge fan of, but there are some pretty unique abilities tucked away in there. At a guess, I'd say the cleric is still superior to the oracle overall, but not as far and above as the 3.5 cleric is to the favored soul.
Of the upcoming classes, I'm pinning my hopes on the Summoner, but the Alchemist could be interesting too.
Edit: Oh, responses to my posts!
Operation Shoestring: Good point - I'll start with the PF version, and if lethality is still too high, I'll tack on HD to that. Right now most PC deaths in the campaign have been vs. save-or-die's and ability score damage though.
Unbeliever: I might just stop by! I'm in D.C., but I stop by NYC every few months to meet with friends and family. The assassin's build is a Minotaur (Dragonlance +0 LA version) Rogue 3/Ftr 2/Barbarian 2/Assassin 6 or something, I believe. She uses poisons and a wounding composite longbow (house-ruled to allow wounding ranged weapons), so with 5 attacks/round after haste the con damage add up very quickly.
As for the -Con on death, it isn't a house-rule that I had ever encountered or used, so I was pretty impressed with it. But if they are making changes that make sense and work well, then I'd say that's a good thing. I mean, they made death from massive damage an optional rule instead of the baseline assumption, which is another thing that just about every game I've ever been in or ran does anyhow.