To my eyes, they don't look as nice as a frame made from tubing, but they look nice enough. Braze-on style front derailleurs are a nuisance, because they limit the sizes of chainrings that can be used. But these days, you can go without a front derailleur anyway.

My one major misgiving is the deletion of the right seatstay on the "Erik" model. If you can put that kind of grievous design blunder into production, what other-- less visible but still serious-- problems might you have made for the end user?