If you are on the fence concerning a purchase of CA, then I would suggest you look at this article here. It provides an extensive overview of CA's functions. A list of reviews to CA and other Convekta products can be found here.
And as always, I would recommend a visit to Aaron Tay's site. He has quite a bit of interesting technical information. Much of it is not specific to Chess Assistant, but I think many of the more technically inclined readers of this page will find his site helpful. While I have not tried it, there are some tricks for getting the Chessmaster engine running under Winboard/UCI compatible programs (of which CA is one). Aaron has the details on making this setup work.
I mentioned some time ago that Convekta has updated the HTML output functions in Chess Assistant 7.1. Much of this work was as a result of Dadi Jonsson, who provided extensive suggestions to the development team. The results of this collaboration are visible at Convekta's weekly site. I think you will agree that the new look is very clean. All told, CA provides the best HTML output of the Commercial programs.
If you think you need additional help on using CA, or want to join a user forum with quite a few CA users, then I would suggest the ChessReviews yahoogroups (membership is free). Although this e-mail list has information on all different types of software, it also contains quite a bit of information on advance features and bug fixes in CA.
Joe Pechie has some info on Winboard engine compatibility with CA 6.1. These results should apply to CA 7 as well.
And last but not least, there is the new Convekta weekly site. This is an interesting site if you want a candid, unfiltered peak into competitive chess. This low-bandwidth site has a very Russian flavor (as well it should), and contains tactical quizzes, annotated games, and commentary.