Lots of helis can barrel roll, EC120, AS350, Hughes 500, Augusta 109 to mention just a few. Done correctly it feels very comfortable !

Have been in a Blackhawk doing barrel rolls several times and have seen a Blackhawk Loop and AS 350's do barrel rolls......... a long time ago when I was younger and stupider!!

roll
 

Someone posted a vid of a B407 doing a barrel roll and loop at an airshow on an earlier post. Rumour has it that the pilot lost his license, chopper was grounded and had to be rebuilt.
Was it worth it?
Dunno, but sure as hell makes for a nice movie clip...

The 407 was doing a slow roll which is a completely different manoeuvre and with different stresses and risks.