Howdy.
This topic comes up all the time...do a search.
Rizoma makes some super nice ones ($$), lots of people like the crg bar end mirrors ($), many use Napoleon bar end mirrors (~$25 each). Some even go to a bicycle shop and use $10 bicycle mirrors.
So I liked the CRG lane splitters, but at $175 for a pair I blew that off and got Napoleons. Less than 1/3 the cost, they work fine (good field of vision), don't vibrate.
It's a personal choice + factor in your $$$ situation.