I have a soloflex, it was cheap. I tried all the exercises you can do on it but I wound up getting free weights, one in each hand is a more natural workout than using a bar. I stand in low karate stances while I'm working my shoulders and arms. I use the soloflex only for a couple of exercises I can't do with the free weights. It is hard to get on the bench and under the bar when it is set up for bench pressing. They go for $100 used. I'm sure the bowflex is better and I'm sure that nothing at home beats a well equipped gym. Consumer reports did a comparison of all the home gym products a couple of years ago, might be worth it to check that out, one that I never heard of was the best by far, can't recall the name.
One thing to note, your connective tissues will build up much more slowly than your muscles so concentrate only on a slow buildup of strength, think in terms of years. If you build up muscles fast you will injure your joints. I focus on shoulder, back, neck and knee strength, not muscle, because the articulations are the weakest part of the body and they have to be built up first before you can build the muscles. The best joint supplements are available from purityproducts.com.
I've been taking it slowly for a couple of years and I got past bursitis, weakness, injuries, all of it goes away if you are careful.
Max