This sounds very much like I expected.
The difference between the magic users seems to tie in with what we've been told in the seminars at DDXP, in that:
1) The default is Vancian spellcasting
2) There are feats (or the equivalent) that let you trade spell slots for things that are more like 4e-style powers.
It looks like the human magic-user has mostly stuck with the Vancian slots, but has spent a couple of feats/slots to get himself an at-will "Javelin of Fire" and a choice of spells that he can do once per encounter.
The elven magic-user has spent all their spell slots (and we don't know how many feats) on a variety of at-will cantrips, some choices of warlock-style blasts once or more per encounter, and some choices of spell that can be cast daily but without prep.
The cleric has swapped his low level slots for a daily out-of-combat healing ability, but hasn't continued to swap out spell slots as he goes up levels, so at higher levels he has those in addition to that ability.
It's almost the perfect example of how the modularity is supposed to work. The thing that would have made it perfect would have been if there had been a third magic user or cleric who had not spent any feats/slots and was purely Vancian.
The thief abilities are interesting too, and again tie in to the seminar info about being able to trade off raw combat power for special maneouvres. For example, he can trade an attack for an evasive action, or trade a double-attack for a single attack doing extra damage in some circumstances, or (at high level) trade an attack for a brief invisible escape.
The note about having "Advantage" rather than "Combat Advantage" also supports my suspicion that the mention of "Advantage" in skill usage is evidence that it is a unified mechanic that works the same both in and out of combat.
And I love the way that the new Haste spell apparently doesn't break the action economy. From the mechanical description, I'm assuming that the flavour text is something along the lines of it speeding everyone up slightly (they get bonuses but not extra actions) and the caster can concentrate on a particular target to speed them up further (so the caster loses their action but the target gets an extra one). That's a great version of the spell!
Skills also seem to be working as in the seminars. Mostly you just compare Ability Score and if it's high enough you succeed. If your score isn't high enough you roll and add Ability Bonus to try to get the target. Skills are flexible bonuses that add to rolls and may or may not also add to effective scores when checking for auto-success.
It seems that attacks are d20+bonus vs static AC; Vancian spells are saved against using a static DC; and "power"-type spells are saved against using a rolled DC. I'm not sure why that difference is there (or whether it's actually a Vancian/Power split or whether there are other feats/factors involved).
All in all, this lines up very nicely with the official info that we've heard, and it's left me very excited about 5e. Now all they need to do is iron out the bumps and it will be a great game.
