Possibly buying Emperor 1

I'm thinking about buying an Emperor 1 (Red Emperor).

The nearby garden shop only has 3' ones. They can order a bigger specimen. I can also order bigger ones for much cheaper on-line. I'm tempted to go with one of the pricier shorter ones because I know it's already stable here, and won't need to worry about potential shipping damage. But I'm torn, of course. I do trust this shop, so that makes it tempting to go with them despite it costing more.

Does anyone know about about how fast they grow?

And does anyone have recommendations for the best place to order one from?

Any general info about them would be good, the plant files entry has very little. I could get a Bloodgood for cheaper, but have been under the impression that Red Emperor would be a better choice (and this is intended for a spot where I would want a big tree ultimately). The tree would get a lot of sun, and supposedly that is okay for them. I'm also hoping it would be cold hardy enough for Colorado. (Primary desires: big red JM that can handle sun and cold. Red Emperor seemed like the best one for those stats, let me know if I'm wrong!)

Last minute waffling after a year of thinking I probably want one of these. ;) Any ol' info would be nice.