Pros:
Outstanding performance, even by Ferrari/Lambo standards. Better accelaration than an F430 (and a Murcielago or Gallard are not even close). However I think the F430 and Gallardo would handle slightly better/more securely.
Lots of bang for your buck on performance and attention. If you can get one for MSRP, you're basically in the same range as an F360, which is a nice car, but not in the same league performace-wise (or repairs/maint cost).
Reliable: I've put 23,000 miles on mine over the past 18 months. Runs exactly as new. Engine is bullet proof, no question about it. Clutch still behaves as new (but I don't abuse the clutch, no burnouts ever).
I think there is very little risk of very expensive repairs.
Decent warranty (3 yrs 36k). Some exotics are only 2 years.
Gets more attention that a Lambo or Ferrari. Appeals to a broader range of people (older people, NASCAR fans, kids, exotic-car guys, etc.) Everyone likes the car.
Surprisingly comfortable! I've made several 8-10 hours runs in it.
Possibly gets less attention from highway patrol than Vipers, Vettes, or exotics...I think some CHP are a little hesitant to ticket this car (not that I would ever deserve a ticket). I had one CHP tell me "no CHP in their right mind would pull this car over!!!" (OK, that CHP was a Ford nut so I guess that would help.)
There is nothing finicky about the GT. No frustrating little electronic problems, etc. The engine is always ready to GO, runs well when cold, will not overheat no matter what (I blasted through Death Valley when it was 118 degrees, with the Air on the whole time).
Very easy to drive. Throttle not jumpy. Long, smooth clutch. Perfect steering feel. Softest ride out of any exotic I've been in, yet it corners and handles extremely well. Loads of grip.
Resale value: I don't think you can go wrong at MSRP. There's a good chance that in 10 years these cars will have gone up (maybe quite a bit). Ferraris and Lambos that are now 10 years old have lost about 30%-50% of their value.
Repairs, etc: It's a lot nicer driving it to a local dealer than flat-bedding it around the state. Big difference there! Plus, you won't have those horror stories of your car being in the shop for 3-4 weeks at a time while they are "waiting for parts".
Cons:
Tempts you to do things you should not do on the street. If you're not a responsible, mature driver then don't think about buying this because you'll kill yourself. Insane amount of power.
Poor luggage and storage space.
Fit & finish not close to Ferrari or Lambo.
Summary:
It just depends what you are looking for in a car. If you want fit & finish, prestige, and performance go for the F430 (but pay $100k more). If you want fit & finish, performace, and attention get a Murcielago. If you want something more rare than an F430 but a daily driver, get a Gallardo. If you just want performace, get a Z06.
But if you want everything (except superior fit & finish) then you can't beat the GT. I'm one of the fools who paid $100k+ over sticker and I'm still pleased. Obviously I wish I had waited, but even so I'm happy with the purchase.
I'd like to qualify the negative aspects I brought up about Ferraris and Lambos by saying that I'd love to have a Murcie Roadster, Gallardo SE and an F430 in the garage too. They're fantastic cars of course and I am not implying the GT is "better". I just thing it's a better purchase if you can only have one of them (again, depending on what you are looking for in your car).
The correct answer is to buy all of them of course!