If I had the money, yes I certainly would. ...
If Atlas-O had to do it over again, I wonder if they would offer the cars piecemeal over time again. They're certainly starting that way again with the recent catalog'd Alaska RR cars. Maybe one or two years MAX, but no way would I ever sign up for the onesy/twosy approach over 5-7 long years again! A lot of unforeseen life/business events can happen in that amount of time. Importer/manufacturer relationships change, and people's interests and life situations change. 
Now that the project is rolling to a close, a 12-car train at roughly $125-$150/car will set a CZ enthusiast back $1,500-$1,800 -- not including motive power. And there are plenty of options for motive power -- both prototypical and fantasy.
Since I'm expecting a full 12- or 13-car train to have a bit of heft to it, I'm planning to put 3 Lionel Legacy heritage SD70ACe's (all powered) up front when I'm in the mood for fantasy running... one for each CZ roadname: CB&Q, D&RGW, and WP. Those Legacy diesels sound superb! 
And they make for a colorful headline of loco power. When my mood tends to more prototypical running, I have WP (F-series) and CB&Q (E-series) ABBA or ABA configs on the roster too.
Either way, passenger trains tend to take a serious chunk of $$$$ out of the wallet, but they're tough to beat when cruising through our miniature worlds of model train wonder. 
David
