I won't bother with a review of the movie here--there are already hundreds of those--but I wanted to (hopefully) add some helpful comments regarding this blu-ray transfer and help out anyone that owns the DVD that might be sitting on the fence.
To my eyes--and I'm a bit of a stickler/nerd about PQ (I'm an ex-cinematographer/photographer)--this transfer looks damn good; it's a HUGE improvement over the non-anamorphic DVD edition (the only other version, save for VHS, available up until now).
Sure, there aren't any supplements to be found here, but if you're a fan of the film, you're likely to already have that awful DVD version. I'd bet anything that any future 'special edition' blu-ray is going to be the same transfer as this blu-ray (it looks damn good; can't see the point of striking another one) with those same supplements found on the DVD recycled--and I'll bet anything that they'll be in standard definition to boot (just like your DVD).
Short answer? If you have the DVD, keep it--and get this for the great blu-ray transfer. You'll basically then own any 'special edition' blu-ray of Good Will Hunting that will be released in the future and at a fraction of the price.