Thank you for this question. Actually we feel that Ektron will be the closest comparable product to ours. It's quite difficult to compare the products since Kentico CMS is quite new and the first version will lack some features, such as versioning or workflow. However we are going to offer these advanced features as well in future versions. Also, Ektron will soon release its CMS 400 with native ASP.NET support, so it's difficult to make the comparison now.

Still, there are few differentiators, I'd like to mention:
1) Ektron is much oriented on XML content. Kentico CMS stores structured data in database tables - one table for each document type.

We believe this approach brings better performance and .NET developers will find it more familiar.

You can e.g. take articles (products, press releases - as you want) in a form of DataSet and bind them directly to your favorite grid control (or use our standard one). At the same time you can take the same articles and transform them using your XSLT stylesheet.
Still, Kentico CMS will also allow you to store "everything in one field" if you prefer this way.

2) Kentico CMS is more like a component - it provides open APIs and controls you can easily use in your applications. It's also "pure .NET" system without any heritage of ASP.

3) Last but not least, Kentico CMS is ten times cheaper than Ektron CMS 300. We want to focus on Web developers who need a cheap, but still professional tool to deliver Web sites to their customers or companies, we don't sell our CMS as an enteprise solution, although it aims to have "Enterprise" features and parameters. With Kentico CMS, you will get a larger portion of the project budget for you.

These are only a few examples of many differentiators you can find between both products. I will inform you as soon as the beta version is released so that you can compare features and philosophy of both systems. I'm sure you will like some Kentico CMS features, especially if you're using or planning to use ASP.NET.