Personally I find it more helpful to play here and then to analyze my games using a chess engine. I am so outclassed when I play against the computer than I start losing so quickly that there is hardly anything to learn from playing in a completely lost position.
ChessMaster vs playing here?
playing against people is better, i'd think. People get into more intersting postions. cause they make mistakes. Also more fun when you have no idea if you'll win or lose (In Chessmaster, you either get crushed, or you 'set it' so you can win)

every person plays differently... most computer engines play the same moves. there is practically no point in playing one. humans are so diverse and intuitive that nothing beats learning from other people.
plus computers in theory just "remember" where to go in certain positions rather than attempting to get in a better one

It seems to be really hard to make computers to play bad chess! My impression is that Chessmaster does really stupid tempo wasting moves in an attampt to play bad chess.
So, I think playing here is a much better way to improve but sometimes family life makes that impossible. It can be quite nice to pause a game vs. Chessmaster when the household chores are calling for you.
Ergo:
Playing live opponents is much better. Especially if you have a chance to exchange some ideas with your "enemy" after the game.

I can't tell what level player you are since you don't have even a unrated game that i can glance at.
But I would guess your fairly new to the game, so i would recommend getting in ALOT of live chess games. Try to play players higher rated then you but at a reasonable diffrence maybe 150 point diffrence max when player higher. It will be discouraging at first but I know that when I play a computer I seem to make moves quicker and with less heart then when playing a real person. You will slowly become more solid in your game, make less blunders, and figure out what openings work for you. Play long games for a while and then try fitting in a few blitz games here in there.
On the side play a number of turn based games which give you the time to consider your moves and read the featured articles which have games completly explain. Use a software to analize your games, im not sure if chessmaster has that feature but im guessing it does.
Hope this helps... Its worked for me, hope you can switch it around and use some of it to help improve your game.
I was wondering what would help me develop more as a player, playing on this website against people or playing the ChessMaster computer or other such programs?