Baines Racing can do this mod (invisibly) to your standard cans, and they certainly sound 'frutier' afterwards. My own bike has had this done - in conjunction with the airbox mod and fatter chip. The bike is now more responsive at all revs, and it has never been a problem at MOT time. (However, a noticeable performance improvement can still be felt when DP carbon cans are fitted).
Appearance is down to personal taste, and I prefer the look of the bike with the original cans fitted. They're less of a target for opportunist thieves too. (The cans on an 888 can be removed very quickly!)
(When it comes to 'must have' accessories, maybe we're all just slaves to marketing hype? After all, Titanium is more abundant than Tin. If you want a bike with real 'bling', get yourself some Tin cans fitted!)