This weekend I got around to playing the Diablo III beta some more, testing the last two classes I hadn't played yet: Wizard and Demon Hunter. Both of which fortunately turned out to be quite fun to play, which means that from the beta I like 4 out of the 5 classes. Comparing the two ranged classes, I preferred the Wizard over the Demon Hunter. The Wizard plays pretty much exactly as you would expect, starting out with single-target magic missiles and point blank AoE, and getting really good once he acquires ranged AoE spells.
The Demon Hunter is a bit more complicated. It is the only class having a split resource meter, using both hate and discipline. Hate powers aggressive abilities, discipline defensive abilities. Discipline recovers much more slowly than hate. Now that might work better at higher levels, but your problem at lower levels is that you can only use 2 or 3 abilities, and putting a defensive ability using discipline on one of these few slots is simply a waste. I did like the exploding bola ability for its fun value, but practically an AoE explosion with a 5-second delay is obviously less useful than the immediate explosions of the Wizard spells.
As remarked earlier, a large part of healing in Diablo III works via health globes that can drop when a mob dies. That puts ranged classes at an inherent disadvantage, because they tend to stand somewhat away from these health globes. The Barbarian and Monk have a much easier time scooping the health globes up, and they both have self-healing abilities. So I would say that the ranged classes are somewhat harder to play. Especially the Demon Hunter, whose defensive abilities at least in the early game are limited to back-flipping or tumbling out of the action, with a certain risk of these moves getting him deeper into trouble by jumping right into the next group of mobs. The Wizard's frost nova is a lot more useful as defensive ability, even with its cooldown timer.
New this weekend in the beta was that the auction house opened. Gold only, obviously, no real money trade in the beta. The AH is apparently modeled on the WoW version, with bid and buyout system, and all the related disadvantages. I generally prefer AH systems in which you can't see what the asking price is of all the other players, because then you don't get those permanent undercutting wars. One innovation is that when bidding you can put in a higher bid amount, and the AH automatically adjusts your bid if somebody outbids you, like on EBay. What is also new is that you search by character, as in "all the chest armor pieces my Barbarian could wear". That has advantages for buyers, but is somewhat cumbersome for sellers who found an item their characters can't use and would like to find out its market value. The beta not having all that many players, and the AH being new, prices still were all over the place. But it was already clear that the only items really selling were those that had good stats for their level requirements. Your average loot drop isn't going to sell for much, and you might be better off disassembling it into essences and crafting something better from those.