I ride a 2003 Bianchi SL3 ALU with a double centaur group - same frame, and the group is one above Veloce, so probably of pretty similar quality.
I chose mine ahead of the 2004 Trek 1500 and 2004 Specialized Allez Comp. For the sake of reference, it cost me £1260, reduced from £1400 because it's a 2003 model.
I've ridden the bike for a couple of hundred miles now, and am extremely pleased - in fact I only just got back from a somewhat strenuous 40-mile excursion on it and my legs are killing me, so the fact that I'm still singing the bike's praises speaks very highly of it! The frame feels very solid and stiff, stiff enough to prevent noticeable chainrub even when out of the saddle (admittedly I'm no sprinter though). This makes it a pretty heavy frame, and for a road bike it's actually a bit of a beast in the weight department. However, I'm perfectly happy trading lightness for durability. The fork is nice and stiff too, and although I don't have enough experience to make concrete statements about the carbon's vibration-damping ability, I can say that after several longish rides over the typically terrible British roads (and this is with tyres at 120psi), my arms don't feel numb or battered.
I have noticed that the steering of the bike is pretty twitchy - I wouldn't want to try riding it no-hands. By comparison, the steering on the Specialized is very stable - sprinting out of the saddle with hands on the hoods, I found that the bike just goes in a perfectly straight line even if you're not really concentrating. With the Bianchi, riding out of the saddle takes a bit of getting used to (depending on your starting point, of course), but I think the extra responsiveness is well worth it. Weaving in between potholes and rocks and dead animals and all the other non-bike-friendly stuff on the roads is effortless, even at speed.
The Campag kit on the bike is great and this is the main reason I chose it over the Shimano-equipped bikes - I just don't like the idea of a shift lever also being a brake lever. The Campag shifting is clunkier than Shimano, in a good way - it's not crunchy or imprecise or slow to shift, it just really lets you know when it's shifted. It's down to personal taste, of course, but I would rather have some feedback than have stealth shifting. If you're getting a 2004 model, I'm guessing it'll have the 2004 Veloce group on it, which is 10-speed, and I've found the 10-speed drivetrain is pretty fussy with cable and limit screw adjustment, so be patient with it. Once you get it dialed in, you shouldn't have to worry about it any more, except for the occasional tweak-up. Also, the front shifter with it's many, small increments is a godsend (I would think especially so with a triple drivetrain) - instead of having to tweak it to perfection to avoid a rubbing chain, you can just trim it whilst riding using the ergo lever. There are those who say this is the wrong way to do things and shouldn't be necessary, but it works perfectly, it doesn't cause any damage, it doesn't affect your riding and it won't void your warranty, That's good enough for me.
Campag's brakes IMO are gorgeous - they have great modulation, and if you need a lot of stopping power, Squeeze the levers hard and they do the job admirably. But the shape of the hoods is a little square for me - this is very much a matter of hand shape, riding position, taste and so on. The faux leather effect on the hood covers is naff, but who cares?
I doubt all the other bits and pieces like wheels, tyres, saddle etc are going to match up, but for what it's worth:
The wheels on my bike are Mavic Cosmos. 24 spokes at the front, radial, and 28 spokes at the rear, crossed on both drive and non-drive sides. They are very true and look like they'll stay that way, the braking surfaces are well-machined, there is no visible welding seam and the hubs roll beautifully. I haven't ridden them enough to comment much on durability but I certainly can't find fault with them at this stage.
The bike came fitted with Continental Grand Prix S tyres. They take 120psi, seem pretty tough and roll reasonably well, but are a little harsh-feeling. I've put on Vittoria Open Corsa Evo CX tyres - they're really light and thin and expensive and will wear out in no time and are puncture-prone, but I love them. If you use these tyres, for God's sake don't go on a long ride without a pump and a couple of spare tubes, or at least a puncture repair kit. IMO the ride quality improvement is worth the hassle.
My only real criticism is the saddle - it says "genuine gel" on it and has a little grey plastic beak-like thing at the front and funny little transparent red plastic inserts (reflectors of some sort?) at the rear. It has a pronounced hump in the middle which after 30 miles or so produces the "Ultima Thule" of bike problems - the numb [censored]. And if you're on a busy street you can't exactly get off and try to massage it back to life, can you? The hump is so pronounced that I think it must squish the plumbing a bit; after a 70-miler I did recently, I tried to pee and suddenly became painfully aware of various organs in the pelvic region that I didn't even know I had.
Anyway, I hope this all helps. I reckon this bike was well worth it - if I ever feel buyer's remorse all I need to do is ride it 10 yards and I remember how worth it it is. If I missed anything or you have any specific questions, post 'em up and I'll do my best to answer. Happy riding!
P.S. If you buy into the whole brand-name thing, Bianchi has to be one of the sexiest - way more suave than Trek or Giant or Specialized. Personally I couldn't care less as long as it works well, but that's just me.