Hi, I've been looking at this a bit recently. I becoming a fan of the one page sites. The better designed websites I've come across recently tended to be one pagers.
There are a few things to think about for users however. If the site is very content heavy, its a challenge to allow user to always know where they are, and how to navigate around.
I also think one page themes work better on mob/tablet devices where scrolling rather than clicking is the more common way to navigate.
Of the two you have selected I'm more impressed with the 'Jarvis' theme. This site is more engaging, and for me the typography works much better. I try them out on a few different devices, phone, tablet, phablet etc and see how they work. Even get a few mates to try them and do a wee user test session.
Good website, also gonna look at it over the weekend.