Here is my list of upside/downside of Aperture - it is a very short list
1) The image rendering is fabulous from my 1Ds-III - the skin tones and gradations exceed LightRoom massively. Aperture appears real and unadorned while LightRoom seems gimmicky and laden with extra cheese somehow.
2) The new book designs are a boost
3) The speed improvement is very very solid - the program is downright brisk
4) The lift/stamp is nice - though the Lightroom interface here appears better
5) the overall file management is faqbulous
1) the contiguous vaults are a tough pill - it would be nice to be able to have a few partitioned vaults.
2) some other minor stuff.
3) the inability to specify an ftp location for web gallery uploads other than .MAC
All in all - for journalistic image management that favours reality over schmaltz - Aperture is a clear winner.
Though - I like the insta-schmaltz of Lightroom - Lightroom is good for taking 200 images and making them all poofy and winsome for a bride.