I never use anybodies L3+R3 ability. Not because I hate it or anything. I just don't think about it.
The only one I never use is Franklin's because the whole point of it would be to dodge traffic during high-speed races/getaways. It's all good and everything until it wears off. Then time speeds up and you go hurdling into the nearest wall trying to adjust your speed to the lack of slowmo.