Boxplots or violinplots?
Hugely dependent on both user and audience preference (violin plots being more unusual could throw people), so it is mostly up to you.

One main reason to go for a violin plot is to give more detail about the distribution, as box plots just give hard stops at the mean, stddev and 2 stddevs. Therefore if you think there is interesting information contained in the distribution between those points go violin.

The other main reason is they're more eye catching on Kaggle ;)