It is interesting that you can find Barnvelders for less. They are a much rarer breed. I like the Barnvelders better as they are double laced where as the Wyandottes are single laced. Lifespan is the same though. I would recommend Barnvelders over the Wyandottes for show quality. Egg laying production is the same. A great place to get chickens both rare exotic breeds and the more common egg layers is from a family in Strasburg on CL.
http://eastco.craigslist.org/pet/5729807058.html They are great folks that share tips and a booklet on raising chickens and help determine the best breed for your family. You can also get organic feed there. They have all age ranges and guarantee sexing which is great for those that live in the city.