I've currently got a Micron end can (no idea which specific one), which is in pretty tatty shape, it's got a bolt missing, scratched up the side and generally pretty scruffy. I've had a chat with my local bike mechanic who reckons that because there's no baffle or anything in the can it's gonna be affecting the performance because, loud though it is, there's no back pressure, and has suggested I look at getting the end can replaced if I can. Now I need to look into getting an oil and filter change, paddock stand, new brake pads, new tyres pretty soon and a Haynes manual, so it's not exactly high on the priority list, but I am interested to see what cans people recommend. Not too bothered about loudness so long as it sounds at least a little bit meaty, but I would like something a bit nice looking.

yes a baffle-less end can will affect the power of the bike.....
BUT it depends IF the prev owner or you have had the bike tuned to THAT tatty end can?

ANY end can(*), headers or air filter change needs to be re-set up.
(*) esp if you used to have no baffles to one with..

my bike runs a "straight through" system.. not a baffle in sight! it runs just fine as it was tuned to the set up it has.
if it aint broke.. danea fix it!