Looks like good fun! Shame its a journey in itself just to get to the place for me! .. still, i might pop along to this Note to self.. get the day off work!
Personally i would go for the kwak.. the ER is a great 1st bike! Dukes tend to be a little on the pricey side for servicing.. Tho it is totally up to you, try them both and get the one that suits you most!!