Go with the 20 inch frame...
...not as cool looking as the 17" but it is still well built.
I'd provide a review of my Worksman experience but, I am waiting to hear back from them on a frame I paid for but never received.
Customer service leaves much to be desired as does the fit and finish. American made, yes, but not as well made as it could be -- serious lack of attention to detail.
It is a strong bike provided you reinforce the post with square steel tubing and epoxy. I have a posting on that somewhere.