Impressive tutorial for newbies and experts alike. Adjustable difficulties and progress ranking makes it enjoyable.
I always get frustrated with many chess software because it is 'too hard', I can never beat it, it is demoralizing. Not with Chessmaster, you can even play with kids (or even monkey for that matter). And chessmaster can comment your gameplay and make suggestions and tips. If you are a competent chess player, you can always crank up the difficulty level and play against The Queen. I think you wont be dissapointed!
I never played online though, so I cannot comment on that. My comments is based solely on offline game play.
There are various chess sets to choose from, 2D or 3D. But I dont like the 3D view as I find it confusing. The 2D sets are nicely done. If you are buying it for your kids there are special interface for kids too so it should be attractive to kids as well.