Wordpress vs Ruby on Rails for e commerce site
I'm building a site very much in the vein of airbnb and relayrides. Peer-to-peer rental. Those sites include: listing your item, people searching for that item by date and location, c.c. transactions, splitting payments btwn the owners of items and me(the site owner), account info, profiles, databases, etc.... The site is designed and I'm interviewing front and back end developers. Areas in which I have little to no experience or knowledge. The 2 best candidates are a guy who works with Ruby on Rails, Cass and HAML and the other will build it in Wordpress and then build it out to add all the functionality I need.
A friend who is a developer of some renown scoffs at the use of haml and the use of any plugins for ruby and says I should have the site built completely from scratch but I don't have $50,000-$75,000 laying around. It will be $10,000 for the ruby guy.
The wordpress guy is fairly accomplished as well. Done work for nike and few other large clients. But wordpress doesn't have much history in the ecom world and I can't find anything as complex as what I'm attempting to do coded with it. Will it be to heavy? To buggy? Security risks? Waiting on a price quote currently.
If anyone can shed light on this or offer advice I would greatly appreciate it. I'm about to spend a lot of money on something I'm pretty confused about. Not a good feeling.