Avon heated grips for me w/ spike ends. Not a terrible installation but take your time as you have to measure and drill into the handlebars. Extremely clean install if you do right.
I use them a lot in spring and fall here in Chicago. Easily one of the top 5 things I have done to the bike.
2nd full season for me with them and no future bike will not have heated grips unless I suddenly move where it is a lot warmer...
Only negative is that the wire on the throttle side makes using something like the Breakaway cruise control impossible. Would like that for longer rides but I have Throttle Boss and that helps a lot on all rides.
Have only run the grips on #4 setting once and that was when I rode when it was stupid cold