I have the fit and love it, but I only do it approx every 3rd day, I add my treadmill and home gym one day and My Fitness Coach in between the two. I haven't tried the Jillian Michaels game because of the bad reviews but I have pre-ordered the Gold's gym and will let you know my thoughts after it arrives and I've tried it out.
My Fitness Coach is excellent, it really works you and in many different areas and the "routine" is different each time.....I really really like this one.
I still like my Wii Fit but find myself doing the boxing and stepping more than anything else. I use the balance games for approx "10 mins" and then do 30 mins of boxing and stepping.
The Wii Sports Boxing is an excellent workout if you do that for 30 - 40 mins. it is a really good workout and it's fun, pretend it's your boss or whoever has ticked you off that day while you workout