why get a car that's that old? If you're talking a new 3 vs a used Milly - it shouldn't be older than a 99 Milly S - Millenia's resale values suck which can be in favor of the new (used) car buyer.
My 2002 Millenia S with almost every option and at the time when i bought it, less than 8600 miles on it would have cost $18750 from a dealer but still has 1 1/2 years left for the warranty. I got it for $14250...gotta love family huh?
If you can find a good deal on a Milly S, preferably a 2002, you might still be covered under warranty for a little while with the car. WIth the new 3, you'll have the full warranty. What's most important...looks...features...price..?
ALso, keep in mind what you'd like to do with the car. If you want mods for the car, the Millenia is certainly not the car for you - short of doing mostly custom work... The 3's will have more mods i'm sure. If you want style...Milly all the way...
-Dave