Well, I don't own a Ruby... but I did purchase a Tarmac. Pretty much the same bike... except it's not a WSD.
I found the Ruby as enjoyable to ride as the Tarmac on my test rides. I would have considered the Ruby, but it was $400 more than the Tarmac (Tarmac was on sale).
I also test rode the Roubaix... but wasn't as impressed. It was OK, but felt sluggish.
I have only ridden my Tarmac for 25 miles... but so far... a very nice ride! Smooth and the shifting with the all Ultegra components... SWEET!
Honestly, I can't imagine why the Ruby would be a bad purchase. I am sure you will get 1,000's of fun miles on it!
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather, to skid in broadside thoroughly used-up, totally worn out, and loudly proclaiming: WOW WHAT A RIDE!!!!"