My first introduction to 3rd edition came after I'd been running another game for quite a while, and one of my players wanted to run a game of his own. So I enjoyed it for the opportunity to be a player rather than a GM. And D&D is very solidly playable for the style of combat it traditionally represents(european heavy armor and weapons). Most other RPGs I've seen that focus on the same sorts of weapons can be a little too...realistic with things like what happens when a 5-pound chunk of metal hits a person at high speed. The hit point abstraction is quite palatable. I find the 1d20 mechanic annoyingly swingy, but I was only too happy to put up with it for some of the fantastic effects D&D permits.
That particular campaign was a good time. It included a few of my favorite moments(notably my aquisition of a +1 worg's head of kobold slaying), though it was starting to get kind of off-balance by the time it fell apart due to the participants going their separate ways. We were just starting to get out of the sweet spot, and it showed.
Things started to sour for me somewhat in a later campaign. The DM for that game had picked up a module about which he was extremely excited, so he asked us to put together some 4th level characters for it. We ended up with a beguiler, a druid, a cleric with a race that had an ECL of 3, and my barbarian who had picked up a single sorcerer level(enlarge person + true strike + enrage = hilarity). Things were a little bumpy, but acceptable, and we were progressing through the module steadily.
Until we ran into the will-o-the-wisp.
We'd managed to work our way up to level 6 or 7 by this time, so it had a CR in a reasonable range of our party level. But we couldn't kill it. All of our casters' spells would just bounce right off, and it went invisible every other round, in addition to flying around, so I was only occasionally able to reach it with my great flail. I was whiffing at it every time it came close enough(I'd like to say smacking it, but it had this crazy high AC), and the rest of the party was buffing me and trying to give me flanking bonuses. Eventually I managed to land a couple of solid blows on it and take it down. In the interim, it had done more damage to the party than any other single monster in the entire campaign. After it was over we made the GM show us the monster manual and found the line that gave us all the trouble:
Immune to all spells except magic missile and maze.
It didn't have too many hit points, a single volley of missiles from an appropriately levelled mage would probably have killed it. A second volley certainly would have. But we didn't have an appropriately levelled mage. So we couldn't hit its AC, which was apparently supposed to be irrelevant, and we couldn't bring magical might to bear because we didn't have the correct spell. We were just out of luck, and that's all there was to it.
That hurt. I don't play heroic fantasy games to feel ineffectual, I have plenty of other sources for that. But that wasn't enough to completely turn me off to the game, and a little while later an idea for a one-shot started rattling around in my head. Something high-powered, a team of level 16s kicking butt and taking names. So I threw some encounters together, quickly invented a couple of traps(I remember being surprised that there weren't any traps with a CR on the order of my party in the DMG), and fired up the game. First encounter: a horde of skeletons! Enough to make for a CR of 14, to give the characters a chance to show off without burning through too many of their resources. They opened the door, saw the writhing mass of bones, and rolled initiative. Druid is up first, he fires off a good-sized area damage spell.
A really good-sized area damage spell.
An area damage spell big enough to fill the room.
And that's it for the skeletons. Minimum damage with a successful save is still sufficient to kill them off. No showboating, no people behaving awesomely because there's only a tiny risk, just the druid naming a spell and the enemies keeling over.
This wasn't the only encounter that didn't go as I'd expected. The CR 16 encounter(a couple of golems) took forever, because the golems I'd chosen had some strange immunities I hadn't accounted for. Those selfsame immunities severely restricted the party's options, so only the first three rounds were interesting. The party circumnavigated my traps with very little expenditure of resources, because they had mobility options that rendered the traps irrelevant. And the CR 17 dragon at the end of the dungeon destroyed the party almost as quickly as the druid had taken out the skeletons.
And that's when I realized that I had no idea how any monster group would interact with any party. The primary tool for that (CR) tells me nothing at all. The way the combats work depends more on whether the party has the specific gear (adamintine weapons for the golems), ability (magic missile for the will-o-the-wisp), or resistances (the dragon was alternating between a sleep effect and a breath weapon; none of the characters could withstand both) for the monsters. If they do, the party wins. If they don't, the monster wins.
So I gave up on 3rd edition. But I'm very excited by 4th edition, because it promises to address all of these issues.
The large scale removal of immunities precisely addresses the problem we had with the will-o-the-wisp and the golems.
Minions are exactly what I wanted in the skeletons fight. The "takes no damage on a miss" effect would have left some from the initial blast for the melee fighters to show off on.
The uniform advancement of attack bonuses and defenses takes out the "rock-paper-scissors" problem of the various saves which is what got me with the dragon.(If reflexes isn't favored, you will die to the breath weapon. If will isn't favored, the sleep effect will put you under.)
In conclusion, yes, I did have fun with 3rd edition for quite a while. I love the sword-and-sorcery style it evokes. I love holding off swarms of the undead with my strong sword arm, and blasting rooms of monsters with my fireballs. I love walking with the elves and the dwarves. I love staring down a dragon and sharing that knowledge that only one of us will survive the battle, and neither of us can be sure of who it'll be. But I hate being eaten by a fist-sized ball of light. I hate having to scrutinize every monster for 20 minutes before I can be sure it's okay to have my players encounter it. I hate realizing that I'm not allowed to make my saving throw because if I have a chance to succeed, someone else can't fail. And I hate losing my newly crafted character because some random orc got a lucky roll.
I'm looking forward to 4th edition because I hope it will provide me with all the things I love without including all the things I hate. Every piece of preview information I see makes me more sure those hopes will be realized.
*Edited for error correction.*