For zone 4 and colder I advise planting in spring,..now it would sit in the ground not doing anything when we have frost and cold set in early which can do some root damage or kill it. Best in spring as soon the ground is thawed out. Transplanting will disrupt the root system, anything grown in pots is fine.

I would tend to agree with Konrad, if you had sandy loose soil you would be able to get more of the finer root system. I find my soil much easier to work with in the spring and the plant will be fully dormant. I find a lot of plants hold their leaves way to late to consider them dormant and then the root system may not have time to get re-established. I have had good luck planting bare root nursery stock in the fall though, these were small 1' foot max plants.

I would wait until Spring...that way, it has a whole growing season to establish a root system. I used to buy end of season plants and found that very few of them survived the winter.

Thanks everyone. I'll wait until spring then. I'll see if I can get my DH to remove the shrub I don't want now though. Then the spot will be ready come spring.