Cleric-comes in Moradin and Pelor flavors. Spellcasting is a mix between spontaneous and prepared, as in you prepare a set of spells per day, and then can use any of them by spending spell slots of the right level. Channel Divinity is turn undead(now a 1st level spell) 4/day. Can wear armor, isn't disrupted by damage, can prepare more spells as he levels up. The moradin one has a feat that can grant disadvantage to enemy attacks targeted against an adjacent ally... 1/round? It says reaction, but I don't remember seeing rules for that. Also another feat that forces enemies that get near you to stop as a reaction, whatever that is. Also at 2nd level can spend Channel divinity to boost melee damage. The Pelor one starts with a Herbalism feat that allows him to make anti-toxins, healing potions (just 1d8) and healer's kit (restore HP during 1 hour rests, dependant on your own HD) by spending 25 GP, up to three per hour. You start with one of those for free if you picked this feat right at creation. Then can then at 2nd level make an holy Aoo centered on them that reveals invisible creatures, and at 3rd level pick a feat that maximizes their healing for free. Even the potions they make.
Rogue-now gets +1d6 sneak attack
per level. It applies to attacks that have advantage. Notice that there doesn't seem to be flanking anymore, but sneaking appears to be a much more viable tactic now (single check, it even gets a chapter for itself, while all other skills aren't mentioned at all). The rogue class further boosts sneaking around. As an halfling you can even hide behind creatures bigger than you (and two free re-rolls on anything per day)! Ambusher feat then gives you advantage when attacking from hiding.... But the hide rules said you got advantage to attacking from hiding already
I guess the diference is that the hiding rules demand you to remain hidden while you attack, while the Ambusher feat allows move out of cover(yes you still need it) and be spoted and and still get the advantage. Can disarm traps, secret thief language. Skill mastery turns any 1d20 roll lower than 10 on a trained skill in a 10. At 2nd level you can get automatic advantage on a check 2/day and can adapt to see better in darker places, and at third level they pick the Skulker feat which makes them not reveal their position if they fail a ranged attack while hiding.
Monster team-They follow their own rules. Heavy enphasis on zerg tactics, like kobolds automatically get combat advantage if they outnumber you, rats and vermings get advantage if at least 3 of them gank a target. There's "leader" monsters that benefit from minions like the gnoll leader healing whenever something nearby dies or the kobold leader granting advantage to its minions when it hits a target (if it had advantage, then it deals extra damage). A Medusa has a save or die, altough you can safely evade it by averting your eyes(disadvantage on all attacks), unless you're caught by suprise, then save or die anyway. Even the dark priests that cast spells use their own rules. Each monster is worth a fixed amount of exp.
Other general stuff:
-You can divide your turn movement before and after your action.
-Dwarves no longer get darkvision, just low-light vision, but are fully immune to poison.
-Elves get flat-out immunity to sleep and charmed.
-No mention of trip/grapple/bullrush, some monsters do have that stuff "built-in" in their special attacks.
-Humans don't seem to get anything special, but they do seem to have slightly more stats.
-You're either trained on skills or you aren't. Backgrounds grant bonus to skills.
-Speaking of which, the DC of non-combat stuff seems to be left for the DM to determine whatever he believes is more apropriate to the situation. So yeah...