I've never actually purchased a universal machine like the one you described but I have researched them because I was sort of in the market for one in the past. My take is not to buy one without first trying one out. Also, when it comes to these type of machines, money talks. The more expensive ones are usually better (but not always the case, you can find some middle ground allowing you to get decent equipment that doesn't blow out the wallet!), meaning you get what you pay for. I would first not buy anything until I could experiment with one and if that option isn't available before purchase, I would know the return policy from whomever you buy the equipment from. I good name brand is also a plus. I good quality machine can cost some $ but I think it's worth it. I never bought one because of space in my house and I figured a gym had more to offer for the money. However, if I had the space I would buy one just to give me the option of working out at home when I am limited for time when going to the gym.