I've run my players through three campaigns under 3e, and we've played through three other one-off campaigns at the same time. Our main game ran from 1st straight on through to 28th level, from 3e to 3.5e. Our Shackled City game went from 1st to 11th, Our Rise of the Runelords game (still-in-progress) has gone from 1st to 12th level. I point this out so you understand that I clearly don't have a problem with 3.Xe, that we've played quite a bit of it and that I'd like to think we have some degree of system mastery.
My players are hardly slouches, either mathematically or critically. Two of my players (a power systems engineer and a DBA) write their own custom excel applications to manage their characters in-game. All of them are college-graduates, except one...and that one is much better at math than I am. Most of my players crunch numbers to optimize their builds. The engineer once performed manual chi-square tests on his dice at the table to make sure they rolled true. Several players have constructed mathematical models of things like power-attack damage curves, skill feat progression tables and so on.
We enjoy 3e and have enjoyed it for years. It has some strengths and weaknesses, just like 4e does. As do all systems.
All that said, my experience is nothing like Bullgrit's or Mournblade94's. I attribute that to a differing playstyle, level differences, party compliment and materials used. I don't consider it a problem...but I also don't consider it to be 'wrong facts'.
For my group, the time of a round and the time of a combat are far from fixed. They become much more variable as play progresses to higher levels. In the famed 'sweet spot', things DO move quickly or at least traditionally do for us. That's because powers and effects are limited, while the players have reached a comfort level with their abilities. At higher levels, things get...dense.
No one is arguing, I think, that 3e's math is hard. I know I'm not. That's not really the issue. It's a question of breadth. We generally use miniatures for many combats. This slows things down if players are trying to determine optimal movements. I suspect folks like Bullgrit and Mournblade94 eschew them, since they haven't mentioned them. Our actual combat descriptions vary depending on the combat. They could be full of detail or just 'you hit', depending on the nature of the battle.
A combat for us might be like this:
Me: The shardling charges and attacks. [Roll] Is your AC higher than 23?
Z: Yes, it's a 25 at the moment. I moved on Total Defense.
Me: OK. Miss then. It slashes ineffectively at you. J, you're up. E, you're on deck.
Z: He takes [rolls] 4 points of fire damage.
Me: For?
Z: J's fire aura is on. When they melee...
Me: Oh, right. Doesn't he have to hit, though.
J: Yeah, he needs to successfully attack first. No hit, no fire damage back.
Z: Whoops, sorry.
Me: No worries.
E: Gotcha.
J: I change my Dragon Aura to DR 2/-. Everyone note that.
D: And don't forget we've got Haste and Prayer running.
J: Not for me, I was too far away when you cast them.
D: Both of them? You were close enough for Haste last round.
J: It's a 30' range?
D: No, it's close range. 25' plus 5' per two levels. But...oh, damn. No two may be more than 30' apart. You're right, you didn't get it.
J: OK. I'm shifting now. I'll do a charge and attack.
Me: Right.
Z: Dude. Move to that square opposite me; you'll cut off his escape and we'll get the flank.
J: Done and done. Got a 25. I guess with the flank that's 27?
Me: Actually, it lowers his AC, it doesn't raise your attack.
J: Same thing, pretty much.
Me: Fair enough. As long as we don't both factor it. Hit. Wait, what route are you taking?
J: This one. [moves mini] Does he have reach?
Me: Yes.
J: Take your shot, I'll risk it.
Me: Ouch. Rolled a '2'. You're safe. What's type of weapon are you using?
J: Longsword.
Me: I know
that. Is it adamantine? Magical? Good?
J: +2 Sword with 1d6 acid...and it's got undead bane.
Me: So it doesn't bypass his DR.
J: Is he? Undead, I mean.
Me: Hmm? Oh, no...he just butt-ugly. He's actually a construct.
J: Crap. So he doesn't take crits, right?
Me: 'Fraid not.
J: OK. 10 points. Should I split out the acid?
Me: Nah, keep it in. Easier that way. Oh, and make me a DC 14 Will save. When you hit him, he lets a keening wail that fills you with dread.
J: [Rolls] Damn. Wait, wait! I use my luck feat! [Rerolls] Nuts. Still boned.
Me: Heh. OK, he drains you for...3 ST.
Z: Drains or ability damage?
Me: Ability damage. I always get those mixed up. Moving on....
And so on. As you go higher in levels, with cohorts (especially spell-casting cohorts), pets, animals, wild-shapes, summoned creatures, planar allies, auras, burst spells, reserve powers, spell effects, special qualities, special attacks, bonus, magic items and so forth become legion. Turns will slow down for most, I'd wager. That doesn't mean they have to, but they can. One of our strategies was for me to turn over a lot of the responsiblity for such details to the players. DMs who don't do this walk the path to madness, IMHO.
Now as I said, turns can and sometimes do go MUCH faster. A combat CAN be determined in one or two rounds. When a 25th level paladin with a baned, blessed holy avenger and a prestige class for demon hunting tackles a Balor while hasted...the Balor sniffs back a tear (his final one) when two of the hits trigger an improved critical. When a 24th level cleric spends a Miracle to strip the demi-lich of his magical protection so the 25th level wizard can hit him with an epic spell version of disintegrate...well, whoever wins Init can often be who wins the battle. And when the PCs gets scores in the 30s and 40s for init rolls...well, they're going to win that bet. Which makes the Dm cry when Kyuss has a stat-block that runs 2 1/2 single spaced pages.
I'm not saying 3E combat is broken or bad. Quite the opposite. It's served us well for years and still does. But I don't think it's incorrect to say that for some people, it CAN drag or feel very swingy, particularly at high levels.